Power Supply Buying Guide

[Bobaganoosh]

Quick Preface: I am willing to update this post as needed with more information (or corrections) if approved or agree to have it taken down if a TPU staff or writer wants to take charge and do a more thorough (and TPU-stamped) write-up. I get asked for advice on this now and then and now that there's a dedicated forum section, I thought I'd put together some recommendations. This guide is intended as a general set of recommendations based on current information and currently released (at time of writing) products. TPU published a guide in 2020 based on PSUs they reviewed and it still has a lot of great information.

SO, you need a power supply. Here are some general recommendations for choosing a supply that's right for you.

TLDR: 1. Figure out how much power you need. 2. Figure out what budget you have and don't skimp on the PSU. 3. Factor in all your other needs (cable lengths, noise, etc.) and read reviews before final selection.

1. How much power do you need? There are several different opinions on the best way to figure this out, but ultimately this is where to start.

• You can use a variety of web power calculators to give you a ballpark of your needs:
  • PCPartPicker - put your parts in and then it will give you an estimated wattage. This one is very basic, but it does provide a breakdown of the larger-power-draw parts.
  • Extreme OuterVision Power Supply Calculator. This one has lots of variables and options that help you really dial in your use-case.
  • Newegg has a simple one, as do many power supply manufacturers (example 1, example 2). You can try putting your parts into several and then do an average (or pick the most conservative, highest estimate). The OuterVision one seems much better than these.
• There are some other considerations to be made when getting this number: Do you overclock? Do you have 12 fans, two liquid pumps, and lots of LEDs? all of these things add power, so it's important to consider more than just the CPU and GPU even though these are the largest contributors.
  
  
• What is your use-case? Let's say you put your parts into PCPartPicker (here's a parts-list just to make an example) and it gives you a wattage breakdown showing 566W-max. Do you go buy a 600W (one notch above that) or do you 750? 1000? This is where use-case (like the overclocking question above) comes in. Do you leave your computer running F@H, crypto-mining, or other high-power workloads when you're not using it? There are multiple factors that can be considered here.
  • Let's say the highest workload for your machine is gaming and you don't overclock. Most of that workload goes to the GPU, usually the CPU isn't maxed out (sure, there are a couple exceptions). So even though your computer parts add up to 566W, you more than likely never draw close to that. So you could pick a supply rated at or just above your "max" (like a 600W) and be fine. Most of the time you're computer is at idle speeds and you'd probably occasionally get into the 300-350W range with spikes a little higher. A good rule of thumb is to go with one about 20% higher rated than your theoretical maximum load.
  • Let's say you overclock and water-cool and you play at 1080p where your CPU is actually running heavily as well...you may need to add to those "stock-maximum" numbers. Do some digging into what other people see with their overclocked similar hardware. Maybe you expect your CPU to run at 280W regularly while the GPU is hitting 300W...you're still not doubling power numbers, but you may have more accessories (pumps, fans, etc.) to add in to the max as well. With this kind of use-case, it might make sense for you to step up from a 600W to a 650W-700W.
  • Now let's say you run something like F@H on your machine 24/7 (when you're not gaming) and you regularly max-out your power-load on your CPU and GPU (and thus your fans as well). You still aren't exceeding that 566W (other than extra fans, lighting, etc.), but you should think about the constant heat-load on the power supply. The hotter you run your parts, the earlier they degrade. So if running a constant heat-load for weeks/months at a time, you may want to inflate the max-power number more than other users just to reduce the heat-load so that you're not running it hot (and loud) all the time. In this rare situation, an 850-1000W wouldn't be ridiculous, because it would then run considerably cooler and quieter for you.
• Efficiency considerations (not efficiency ratings yet, but I wanted to bring up a topic I've seen about using the efficiency curve when it comes to selecting your power supply): There's a point often made about trying to plan for the highest point of a power supply's efficiency curve. While it is true that a power supply is not at it's most efficient operating point at maximum load, it's nowhere near the most important consideration. Here's an example of a titanium rated 1000W power supply. It is most efficient in the ~250W-load region. If you were to make a decision on this factor alone, you would have to chose this supply for a computer that has an i5-14500 and uses integrated graphics-only. You'd spend ~$250 on this titanium rated supply in the hopes of saving a dollar a month in energy bills? That just isn't going to be worth it. You can save some money here by not buying a supply considerably more powerful than you need.
  
  

2. Efficiency Ratings (Bronze, Gold, Platinum, etc.). Let's not get carried away.

• If you leave your PC on 24/7, you should care about getting the most efficient power supply you can afford (reasonably anyway). If you don't, it becomes considerably less important, with some caveats. The price differences can vary quite a bit from minimal differences between Gold/Platinum, to huge jumps. The price of Bronze (and I wouldn't even recommend buying one that has no rating) is usually much lower than Gold+, but those are generally for budget-builds.
  
  
• Here's an older thread that still has some good information. With respect to the efficiency rating itself, it's important to consider your use-case again and if you spend 80% of the computer's life-time at 20% power load, you should look at the efficiency numbers there when comparing two power supplies. For example, if PSU A is Gold-rated and PSU B is Platinum-rated, but PSU A is just as efficient at 20%, but drops below the requirement at 100% load, you're not benefiting by paying the price difference to buy the Platinum power supply. Because PSU A didn't meet the requirement at 100%, they can't call it Platinum, but it is just as efficient for your usage. The thread linked put some charts together to compare savings, but I think they assumed different power loads at constant-usage, so if you don't turn your computer on every day or all day, this may be a bit exaggerated.
  
  
• Your electricity costs where you live can make a difference. For most people, it would likely take years to make up the difference in price between Gold and Platinum or Titanium from the energy savings, but there are always exceptions and some countries/states/regions charge considerably more for every kWh and it can make it worth-while to go to a more efficient supply just because of the efficiency rating.
  
  
• Caveat: There's one primary system that power supply companies use to structure their product-stacks and that's the efficiency rating (outside of side-mount connectors, colors, lights, screens, etc.) as a general rule. What that means is that they probably put more bells and whistles (from a component-quality and circuit-topology perspective) into their Platinum power supply than they did their Gold or Bronze. So when you buy the Platinum supply, there's a chance that it also runs cooler and quieter than the Gold supply, as well as being more reliable in the long-term...but this isn't a guarantee. The only thing the "Platinum" or "Gold" ratings guarantee is efficiency ratings. While more-efficient circuits will result in less heat in the power supply, they're not always more reliable. I would say they have a tendency to be in this application, but definitely not always. Picking Bronze and below power supplies, however, can be a minefield. This is where companies really tend to cheap out on parts and while there are several out there that are surprisingly good quality, there are a huge assortment of really terrible power supplies at the $75 and under level that you have to watch out for. This gets us to the underlined, italicized, and bolded section below...

3. I know what power range and efficiency I'd like, now what?

• Here's where it gets a little interesting. Usually, your next step is going to be sort by budget, but you're also going to want to start narrowing down to specific models. You'll want to consider things like "How many devices do I need to power?" (less common question these days), "Do I plan to upgrade to a higher-powered GPU/CPU in the next couple years?", "Is color important to me?", "How big is my case and what cable lengths do I need based on where the power supply and other components are?"
  
  
• One thing that has made all of this simpler (even narrowing down on the power rating selection) is that ever since the GeForce RTX 3000 series launched (and 3080/3090's had huge current spikes that a lot of existing power supplies couldn't handle), a lot of new power supplies have launched. This has led to most newer model supplies having a much higher surge-current tolerance than older supplies. With older supplies, you would want to spend a lot more time looking into the power spikes of a GPU and then adding that to your max-power estimate of the system when picking a power supply rating just to make sure it wasn't going to trip and shut down on you mid-gaming-session. There were a few supplies that launched after that as new versions of existing supplies, but the RTX-4000 series then launched with a new connector, spurring a full suite of new power supply models from every PSU-company. Newer power supplies with "ATX 3.x" and then later "PCIe 5.0" ratings started launching in droves. These more modern supplies usually have a 12VHPWR or 12V-2x6 output connector(s), 12V-2x6 being the newer and much safer version that are designed with cables that go directly to RTX-4000(+?) series cards. The more important feature though, is the specification requires that the power supply can handle twice the rated power to that video card for short durations. That's a simplification of the spec, but without making this post even long than it is, this has been a huge benefit to users in that power supply companies had to make up for the curve-ball of new GPUs drawing much higher current spikes than they did before and now we have more robust power supplies. What that means at the end of the days is you can buy a power supply that has a dedicated GPU-connector rated for 450 or 600W and it should undoubtedly handle that load (this rating changes based on supply and video card, so you need to make sure they match). You then just need to look at the rest of the components and make sure there's enough remaining headroom. Going back to that example before of the 566W computer, you could likely buy a 650W power supply like the be quiet! Pure Power 12M (just an example) that has a dedicated 450W PCIe 5.0 rated connector for the GPU.
  
  
• Think ahead! Power supplies can last a very long time compared to the rest of your components, especially if you buy a high-quality supply. Here's where instead of making the decision to buy just more power rating than you need, you buy something that can handle a big upgrade in the future. So you only need a 600-650W supply today, but you've got one of those nagging voices in the back of your head saying "Next year I'm buying a 5090/RX-8900TX" (I'm guessing at model numbers for AMD, not sure what they're launching next gen yet) and you know that 6-18 months from now, you'll need more. The AMD RX7000 series avoided the new connectors, but the RX6000 and RX7000 series still had higher power draw and current spikes than older system so the new specification still help even if you're not using that connector/cable (or using adaptors). If you don't want to replace the PSU at the same time you buy an upgrade-GPU, buy the bigger one now. I'd personally recommend a model that has a 600W-rated PCIe 5.0 connector(s) on it (like this SeaSonic VERTEX GX-1000 for example) if you do intend to buy high-end GPUs in the future because we don't really know where the next gens are going to be limited and you may regret a 450W-limited one if you had your heart set on a 5080/5090 and they need more (let's see how smart/silly this recommendation is if the post is still here next year).
  
  
• The most important thing that you should do is READ REVIEWS. This cannot be over-stated. Things like the cultist-network tier list are a good reference, but not always complete. I like to recommend (once you've narrowed down to a few models) reading as many reviews as you can find. Look into a company's warranty and return policies, user experiences, and history. Some will surprise you, both positive and negative, so don't just assume that Brand X is always good or always bad. TPU also has a review databasethat shows their reviews as well as other ones their aware of for any power supply they've heard of (as well as other parts, but this thread is for PSUs). It even sorts by year, which can make it easier to find more recent reviews.
  • Things to look for in reviews as some are better than others: Did they do any tests? If so, how does the supply you're looking at compare to others in the same price/performance bracket? A site like Tweaktown might open a supply and tell you what parts are inside, but they don't have any data while TPU, Tom's Hardware, HWBusters, (and boy do I miss JonnyGuru.com and OklahomaWolf's reviews) might have some actual test data showing things like transient response, load regulation, ripple suppression, and vampire power. Sound and thermal levels might be important to you as well depending on preference and use-case.
  • A good review will go into depth about the regulator topologies used, but you don't need to be an EE or expert to understand what that means to you. Hopefully they explain if that particular topology is generally a good or a bad thing (and why), but usually the end result is that it impacts the efficiency (and thus heat inside the PSU), regulation quality, and sometimes noise (audible-noise). Often the fan is the loudest part of a power supply, but sometimes a really cheap poor quality power supply can have a noisy circuit that is very irritating. If the review shows you the difference between efficiency, regulation quality (for example), etc. of different supplies that you're comparing, that's the end result of those different circuit topologies and component-selection and why it's important.
  • Another place you can look if you really want to dig is reddit, Newegg reviews, and manufacturer forums. The EVGA G+/P+ series for example had really bad coil whine and there were several forum posts and user reviews around the internet describing how they seem to work alright, but they're quite loud and annoying. Newegg/Amazon reviews can be a minefield, but sometimes it is helpful to look for medium-to-bad reviews and see if there are any trends. This can be troublesome though, as a lot of times web-stores like this won't make a new page when a slightly newer model PSU comes out that fixed some problems with the previous version. There were several different variants of the Corsair Rx series for example and often the page would have a "(2021)" with the model name or something, but reviews go back years before that...just bear that in mind when checking user reviews and they can still provide some good information.
  • The graph above of the Dark Power 13 efficiency came from a Cybenetics test report in their database. If they've looked at the supply and you want to do some deep dives into the data, those are pretty awesome.
    
• OEM Considerations. As mentioned above in the recommendation to read reviews and not just trust (or distrust) a brand entirely, OEMs play a role here too. The OEM is the company that actually makes the power supply (in this case) for the company who's brand-name is on the supply. As someone who spent a lot of time on EVGA's forum, I can use them as an example. They've used (at least) Super Flower, FSP, SeaSonic, and I believe ChannelWell as OEMs and even if you look at just the FSP-made supplies, some were good and some were bad. Leaving out which OEM was which, here are some examples: Original SuperNova G-series: pretty good, G2: great, G3: great, G5: bad, G6: good, G+: bad, G7: decent, P2: great, T2: great, P+: bad, P6: decent, etc. They had some really good supplies and some fairly bad supplies, all at the "high-end" of their product-stack, some on each side of the scale from the same OEM. So the responsibility lies with you to read reviews and try to find out if that particular supply your considering is well-made.

--Let me walk start to finish through an example, just to cut through the wall of text and show what I mean:
1. I put my components (not including my custom water loop) into PCPartPicker and came up with ~877W. Some considerations: I have two D5 pumps, 13 fans, two LED strips, and probably a device or two I'm forgetting, plus I like to overclock...so there's a chance that I run my GPU up to ~600W and my CPU at 300W (well, I've seen more, but not at the same time as the GPU was maxed out...and in normal gaming scenarios it's more like 115W, but I probably didn't have all these numbers before-hand, so you can only go on best-guestimates), so I want to be perfectly stable, quiet, and cool while pulling 950W. Is it going to do that all the time? NOOO, but I'm an engineer and I'm programmed to think worst-case, so I'm going to pick a supply based on that. Burt Gummer once said "when you need it and don't have it, you sing a different tune." That said, nothing I'm doing justifies a 1300-1600W power supply. I could probably use a 1000W that is rated to the new ATX 3.0 specs and be just fine, but I'm also going to open myself up to 1200W so I'm never even being that hard on it (and it runs super cool).

2. I don't leave it on 24/7. I game with modern games and do some overclocking benchmarks for fun, so it has to meet my power requirements from #1, but I'm not going to notice any efficiency differences between Gold/Platinum. That said, I want it to be reliable and last a long time, so knowing the PSU companies only put the top quality parts in Gold+ power supplies, I want to buy at least a Gold-rated supply. I'm open to Platinum+, but I don't think I need it.

3. I'm probably not going to buy any parts significantly more power-hungry than these very power-hungry (sometimes) parts, I don't have a brand preference, but I do want to weed out completely unknowns...let's go through some of the PCPartPicker filters (which can also be done just as easily on sites like Newegg, Amazon, Micro-Center, Best Buy, etc., but most people all over the world seem to be able to use PCPartPicker, so I'll just stick with that for this example):

• Efficiency: Gold, Platinum, Titanium
• Wattage: 1000-1300
• PCIE 12+4-pin 12VHPWR Connectors: 1-4
• Because I do have some personal preference here, I'll narrow down brands to: Asus, be quiet!, Corsair, SeaSonic, Super Flower, and Thermaltake. This is subjective and if you don't already have experience or preferences here, leave it open to all and read reviews. There are some good supplies from Gigabyte, MSI, Antec, and others for example, but I just wanted to narrow it down for this.

If I sort by ratings, the top choices are: SeaSonic VERTEX GX-1200 ($194), be quiet! Straight Power 12 ($199, the supply I actually own, look at that), Corsair RM1000e (2023, $159), Asus TUF Gaming 1000G ($149), and Thermaltake Toughpower GF A3 ($164). I see a couple down towards the bottom that I've read great reviews for, but there are no ratings posted on PCPartpicker, so there are always going to be flaws just going from one site. At this point, I'd go through the ones on this list that fit the rest of my requirements for price/performance, cable lengths, color, etc. and start reading reviews. Based on when I purchased mine, I don't think the SeaSonic or Asus was available (not many with dedicated PCIE 5.0 connectors were at the time I bought mine), but this is where it gets subjective and you have to decide from the reviews you can find what pros and cons are most important to you. the be quiet! one fit my case/build well, had cables that look nice, and I've had great experiences in recent times with that company for other parts, so based on reading some great reviews for that power supply, I went for it (my first PSU from them) and it has been great so far. I don't know 100% certain that it's running cool because there are no exposed sensors and it's buried in there, but I can't hear it ever so I can only assume based on the fan never spinning up much that it's got a pretty easy life in there. I did end up with a Platinum supply (I would have happily looked at more Gold-rated supplies if they were available at the time), and it has a 10 year warranty, so a high-end supply like this should last me a long time.​

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Just to add a closing thoughts and general information section...I don't write many posts like this, so I'm sorry if it was a bit rambling or not formatted as well as it would be by the folks who put out more big threads. I also wrote it in chunks in between other tasks so I had to keep coming back to it, proofing, editing, etc. I used several different power supplies as reference examples, but I didn't do that to recommend those supplies specifically, I just picked some supplies I'm a bit familiar with for one reason or another that had information or features pertinent to the discussion topic. We all have our favorites. My personal computer is not a budget build (obviously) so that list of brands I narrowed down to in my example is reflective of that. For example, I was trying to help someone on here find something for a build they were working on recently and ended up recommending a white Gigabyte power supply because it was just barely within their budget, they required a white power supply, and the reviews were good for that particular model.

If you've read this whole thing, please provide some feedback. I'm all for constructive criticism, so feel free.

 

[#22]

Such guide should start with TLDR version or one-three essential sentences before each paragraph - the best guides are ones giving the most knowledge with least words and people vary with interest in details

After getting to know the basics like compatibility (size; cable length), calculating power needed, efficiency or why it's worth to go ATX 3.X, topic in practice is as simple as not buying PSUs with no reviews online. Preferably reviewed and recommended by mentioned here, the best addresses. Then buyer will notice that there're many totally comparable PSUs for the money and it's the core problem here. When there's really no significant difference between them like e.g. longer warranty or modular cables, man should go with the quietest. Comparable noise info can be taken from using one reviews source or Cybenetics PSU database. Noise is the only aspect noticeable on daily basis and it will decrease the problematic choice to one(s) quietest.

 

[64K]

I'll just throw in my 2 cents worth on energy savings by choosing a higher efficiency rated PSU. I see it pretty often that a Platinum rated PSU is superior to a Gold rated PSU. The rating isn't about quality though. It's about efficiency. Use cases vary but for me how much money do I save by going Platinum? My gaming rig draws an average of 300 watts while gaming. On average I game about 3 hours per day. My electricity costs 14 cents per kWh. A Platinum rated PSU is around 2% more efficient than a Gold rated so my savings by going to Platinum rated:

(3 X 365 X 300 X 0.02) / 1000 X 0.14 = 92 cents savings per year by going Platinum for me.

If your rig uses more watts or you run it more or you pay a higher utility rate then just punch in the numbers and see.

 

[taka]

What matters most to me when getting a new PSU is:
- the OEM, not the label maker
- parts used and platform
- 16AWG cables
- fan noise
- electrical paramaters in Cybernetics datasheet
- price ofc
- reviews by established sources

 

[_JP_]

My two cents as an additional tip: UPS'es (not budget ones) are overlooked but can save your PSU if it is a dodgy unit, and for all of them it reduces the noise the primary filter gets besides increaseing the efficiency, because they already do the bulk of the work of cleaning the sine (many times compensating your house's electrical and the utility delivery) and mitigating spikes or dips. Not to mention that you can alter the UPS's Vout to accommodate a better working level for the PSU.
In the EU, most quality units are better working at 240v.

 

[QuietBob]

@Bobaganoosh
An excellent guide, factual and very well written! I'm sure a lot of people will find it useful

My electricity costs 14 cents per kWh ... 92 cents savings per year by going Platinum for me.

A lot depends on local electricity pricing. It's true that most people won't see meaningful savings with a Platinum-rated PSU over a Gold-rated one.

But where I live in Europe the 5% difference in efficiency between Gold and Titanium translates to nearly 0.10 savings in local currency per kWh, tax included. Imagine saving 10 cents per 10 hours of light use (100 W power consumption). Or every two hours of gaming with a high-end GPU maxed out (500 W for the whole system).

Depending on the user's habits and location, those 10 "cents" may start adding up very quickly.

 

[Bill_Bright]

When it comes to choosing the correct size PSU for your new or upgraded build, I agree that PCPARTPICKER does a pretty good job at suggesting a suitable size. But IMO, there's an easier solution (unless, maybe, you are already using PCPARTPICKER) that is better and more accurate.

The right way to determine the proper size needed is to research all the components, determine their maximum power demand, add them all up, and that is the minimum supply you should get. But that takes a lot of time and work. So I recommend using a good PSU calculator and the best and only one I use and recommend is the eXtreme OuterVision PSU Calculator. This will calculate your minimum needs and recommend a suitable size for those needs.

Plug in all your components. Be sure to plan ahead and include all the hardware you think you might add in 2 or 3 years (extra drives, bigger or second video card, more RAM, etc.).

I recommend setting CPU utilization to 100% and Computer Utilization Time to 16 hours per day. These settings will help compensate for component aging, and add a little extra padding to the results in case there are unplanned future upgrades. This will also result in a little cooler and quieter operation as the PSU will not need to work as hard and may allow its cooling fan to run at a lower, thus quieter speed.

Note that no calculator or parts site wants to recommend a PSU that is underpowered so they all pad the results, some more than others. The eXtreme OuterVision calculator is and can be the most conservative (a good thing) for 2 main reasons. (1) They have a team of researchers on staff constantly researching components for us to keep their extensive databases accurate and current. And (2), it is the most flexible and has the most extensive databases of available options you can enter. For example, in addition to an extensive list of CPUs and graphics cards, it lets you specify number and size of case fans, alterative cooling solutions, USB devices, number and types of drives, and more. This allows it to factor in all possible components to accurately calculate our needs, rather than just guess or use arbitrary numbers as lessor calculators must do.

The eXtreme PSU Calculator ensures you buy a properly sized PSU for your needs. One that has a little extra headroom for future upgrades, but not one that is WAY too big and a waste of your money.

As a side bonus, it will also recommend a suitable UPS size and allow you to easily publish the calculation results too. Nice!

Don’t try to save a few dollars or trim the budget with a cheap power supply! Digital electronics, including CPUs, RAM, motherboards and today's advanced graphics cards all need good, clean, stable power. The choice of supply is arguably the most important purchasing decision you will make in your new build or upgrade. A good, well chosen supply will provide years of quality service and upgrade wiggle room.

 

[Bobaganoosh]

Thanks for all the feedback so far! Snipping some specific comments:

Such guide should start with TLDR version.

I agree. I'll have to work on what that would look like here.

... A Platinum rated PSU is around 2% more efficient than a Gold rated so my savings by going to Platinum rated:

(3 X 365 X 300 X 0.02) / 1000 X 0.14 = 92 cents savings per year by going Platinum for me.

If your rig uses more watts or you run it more or you pay a higher utility rate then just punch in the numbers and see.

Yes, I tried to make exactly this point. For many people, it would take years to make up the cost difference (depending on the cost difference lol)

What matters most to me when getting a new PSU is:
- the OEM, not the label maker
- parts used and platform
- 16AWG cables
- fan noise
- electrical paramaters in Cybernetics datasheet
- price ofc
- reviews by established sources

I agree, with the only exception being that every OEM still has good and bad supplies. You can't just trust that all skus from a particular oem are going to be good (or bad). That's what the reviews are for though.

... A lot depends on local electricity pricing.... .

True! I may revisit the note here to just suggest that research. The existing article I referenced talked about that, so I didn't want to repeat all the information.

... . So I recommend using a good PSU calculator and the best and only one I use and recommend is the eXtreme OuterVision PSU Calculator. This will calculate your minimum needs and recommend a suitable size for those needs.

...

I appreciate the tip on the better calculator. I usually do the math in my head based on researching each part before I buy it, but an easy to use calculator with more variable input would be really helpful to most people.

 

[Bill_Bright]

I appreciate the tip on the better calculator. I usually do the math in my head based on researching each part before I buy it,

Thanks. One of the problems researching parts is graphic card makers, for example do a lousy, often misleading job in their recommendations. For example, they seem to arbitrarily pick one CPU and assume everyone is using that one - and even then, some don't even specify which CPU so users don't know which way to go is adjusting their demands.

They may also say something like "32GB of RAM" but don't say if DDR4 or DDR5. Nor do they say 1 x 32GB, 2 x 16GB, or 4 x 8GB. Surprisingly, 1 x 32GB uses about the same as 1 x 8GB. This means 4 x 8GB uses substantially more than 1 x 32GB.

The eXtreme OuterVision PSU Calculator allows users to be specific for a much more accurate estimate. This allows the user add a more realistic buffer, if they choose to.

 

[dirtyferret]

@Bobaganoosh , well done. I knew you would be a good addition to the forum . I would add two little things 1) power efficiency labels can also have temp ratings such as 25c, 30c, 40c, 50c. So a gold unit rated at 30c will not necessarily offer gold efficiency in a hot PC case that hits 45c+ (hence your read reviews comment) 2) sometimes efficiency ratings can be nothing more than marketing. Superflowers new platinum pro 1000w unit does cybenetics platinum but so did the gold version which uses the same platform. In fact pushing the platform to platinum seems to have created more issues so once again read reviews 9as you stated)

What matters most to me when getting a new PSU is:
- the OEM, not the label maker
- parts used and platform

OK, you are entitled to your opinion but the OEM can only provide the product the brand pays for. Platforms are nice but if you cheap out on parts even the best platform can't overcome a cheap fan that stops working and parts that put the PSU out of spec. Also, if there is any warranty issue with the PSU its the brand you deal with not the OEM for a replacement.

. One of the problems researching parts is graphic card makers, for example do a lousy, often misleading job in their recommendations.

the PSU manufacturers allowed the GPUs to be the tail that wags the dog, granted as a company they are much larger (Nvidia & AMD vs CWT, Great Wall, HEC, etc.,) but they GPUs really force the PSU to keep up with then rather then the PSU forcing the GPUs to stay within parameters

 

[Bill_Bright]

rather then the PSU forcing the GPUs to stay within parameters

I am not aware of anyone ever suggesting or implying PSUs force the GPUs to stay within parameters.

The only forcing that way is simply due to the limitations of the circuit at the wall outlet/breaker. But that, of course, is for the whole computer, not just the graphics solution.

 

[dirtyferret]

I am not aware of anyone ever suggesting or implying PSUs force the GPUs to stay within parameters.

I'm saying the PSU should do it but they don't or better yet do a better job of working together

 

[P4-630]

I plan to buy a Be Quiet! Straight Power 12 1200W Platinum.
Don't care much about electricity usage, I just want a real good build this time around.
I got solar panels so....

 

[#22]

Thanks for all the feedback so far! Snipping some specific comments:

I agree. I'll have to work on what that would look like here.

It's good to look from the perspective of typical knowing nothing PSU buyer - he wants to know exact minimum to make possibly good decision. No point of educating him in the matter so interesting to the point he has never been interested in before.

E.g:

Capacity: just linked legendary OuterVision calculator everybody links, but maybe there're even better ones. Not more to say needed. At most could be added that going capacity doubling system load tend to result in the best efficiency and going higher wattage option of given model usually leads to lower PSU noise, but both are things to be checked.

Compatibility: form factor and length need to meet chosen case requirements. Before making a final choice, it's worth to make sure that included connectors and cable length meet needs. In general preferable is ATX form factor.

Efficiency: higher results in electricity savings, but calculate them first before paying premium for more efficient PSU. There's also tendency of higher efficiency PSUs being better, longer lasting and quieter, but these're another things to be checked.

ATX 3.X being worth or not: it mostly importantly saves from shutting pc off by power spikes, but also saves from using cable extensions which are never welcomed.


It's all such guide-seaker needs to know. There's no point of educating him in any technical stuff like what is ripple or capacitor. Then he only needs to choose from models recommended by linked below guys in type of Aris - it saves him research or asking what models are good and worth buying and there should be some available in his region. At most he could also suggest with linked noise data from Cybenetics.

It's simple as that, so should be kept that simple :]

 

[Lost_Troll]

One thing most people forget is how many USB devices they might hang off of their USB ports, like hard drives/cameras/cell phones and so on. So, you should add some addental overhead for these types of items, like 30 watts to 50 watts.

 

[Bill_Bright]

One thing most people forget is how many USB devices they might hang off of their USB ports, like hard drives/cameras/cell phones and so on. So, you should add some addental overhead for these types of items, like 30 watts to 50 watts.

I note the OuterVision Power Supply Calculator provides for that by allowing users to include in their calculations up to 20 connected devices (USB2, USB3, Firewire, LED controllers, LED strips, card readers and more) in addition to the keyboard and mouse. No need to add additional overhead.

HOWEVER - computers have a limited number of ports, typically with multiple ports controlled through a common internal hub (depending on the specific motherboard and case). I typically advise AGAINST adding a large number of connected devices to a single port. In fact, I prefer one device per port UNLESS they come with their own external power source. This ensures the current demands through the USB port do not exceed the capacity of the port.

If you have multiple external USB drives, for example, and a limited number of USB ports, it is better to use an external, self powered USB hub connected to the computer's USB port, then connect the drives to the hub.

 

[Lost_Troll]

I note the OuterVision Power Supply Calculator provides for that by allowing users to include in their calculations up to 20 connected devices (USB2, USB3, Firewire, LED controllers, LED strips, card readers and more) in addition to the keyboard and mouse. No need to add additional overhead.

That is good to know, but I doubt that all of the power estimators/calculators have that level of detail.

HOWEVER - computers have a limited number of ports, typically with multiple ports controlled through a common internal hub (depending on the specific motherboard and case). I typically advise AGAINST adding a large number of connected devices to a single port. In fact, I prefer one device per port UNLESS they come with their own external power source. This ensures the current demands through the USB port do not exceed the capacity of the port.

The number of ports does not matter to a point as much as the power wattage they can supply. USB 4 can be up to 100 watts depending on the voltage supplied. Also, there were a few mother boards that had more than 3 USB 4 C ports.

From the USB WiKi Page....

Power delivery[edit]​

USB4 requires USB Power Delivery (USB PD). A USB4 connection needs to negotiate a USB PD contract before being established. A USB4 source must at least provide 7.5 W (5 V, 1.5 A) per port. A USB4 sink must require less than 250 mA (default), 1.5 A, or 3 A @ 5 V of power (depending on USB-C resistor configuration) before USB PD negotiation. With USB PD, up to 240 W of power is possible with 'Extended power range' (5 A at 48 V). For 'Standard Power range' up to 100 W is possible (5 A at 20 V).

Thunderbolt 3 compatibility[edit]​

The USB4 specification states that a design goal is to "Retain compatibility with existing ecosystem of USB and Thunderbolt products." Compatibility with Thunderbolt 3 is required for USB4 hubs; it is optional for USB4 hosts and USB4 peripheral devices.[20] Compatible products need to implement 40 Gbit/s mode, at least 15 W of supplied power, and the different clock; implementers need to sign the license agreement and register a Vendor ID with Intel.[21]

If you have multiple external USB drives, for example, and a limited number of USB ports, it is better to use an external, self powered USB hub connected to the computer's USB port, then connect the drives to the hub.

USB spec is changing in a way that powered port hubs are going the way of the dodo.


To me, I would just add as an observation that USB power delivery load should also be taken in account if your power estimation/calculator does not have this function.

 

[bonehead123]

"Scotty, we needz MOAR POWAH" - CPT Kirk

So to summarize...

Once you get a fairly accurate estimate of your needs, then turn your attention to choosing a high-quality, well-made unit from an established name brand with a good warranty and lots of reviews/test reports...

Gotta remember that the PSU really is the heart of any pc, so if you skimp/cheap out on it, you can look forward to many, many troublesome issues like BSOD's, random shutdowns, fried cables & components, goofy peripheral behaviours etc...

Unless of course you enjoy those things, then by all means, go cheap & go weep

 

[Bill_Bright]

The number of ports does not matter to a point as much as the power wattage they can supply.

Ummm, did you read what I said earlier? That's pretty much exactly what I said. The difference is, you said "power wattage" and I said "current". Same difference!

Ohm's Law and its derivative, the power formula for DC circuits (P = E x I), defines watts (P) as voltage (E) x current (I). Since we know the voltage is constant, the wattage will be determined by the current. So, as I said above, users need to be concerned the "current demands through the USB port do not exceed the capacity of the port."

You talk about USB4 - yet USB3 and even USB2 are still widely used - even on brand new boards and cases. For example, the ASUS PRIME Z790-A WIFI does not even have a single USB4 port.

Important to remember, USB-C is not the same thing as USB 4. That board has several USB C ports, but C defines the connector, not the protocol and those USB-C ports support USB 3.2, not USB-4.

but I doubt that all of the power estimators/calculators have that level of detail.

Please read through the thread to learn what has already been said.

As I also noted above, the only calculator I use and recommend is the eXtreme OuterVision PSU Calculator. And I went on to explain the reason why is because it is "the most flexible and has the most extensive databases of available options."

Regardless, your point is rather moot anyway. What is the alternative to using a good calculator? Guessing? No! You must research each and every component individually then add up the power demands, guess how much extra buffer/overhead you need, then make your choice. And that assumes the component specs will even list the power requirements - many, sadly, don't.

 

[SalemTheKit]

I really love this guide so far, but I do have ONE minor nitpick in regards to your final example at the end. Given that people who view this thread will likely be newcomers, and likely get lower-end parts as a result, it might be worth trying to show an example build that would be more akin to getting a 550w to 650w power supply because that's what the gigantic majority of PSUs sold online are rated for. I know people who may get overwhelmed reading all this to begin with and just immediately look at the 650w warning and 1000w example at the end and assume they need that. I've had far too many friends overbuy on wattage numbers when they could've gotten a much higher-quality PSU at a lower rated wattage for the same price. Overall the guide is fantastic and I do genuinely like the example at the end but it's just something to keep in mind given the kinds of people I've guided towards PC builds in the past.

 

[dirtyferret]

I've had far too many friends overbuy on wattage numbers when they could've gotten a much higher-quality PSU at a lower rated wattage for the same price.

I see plenty of people on this forum and others who do that. Frankly as others have said, you have to do your own research for your parts. For gaming builds, most web sites offer total system power (some even at peak and avg) for gaming with GPU reviews and flagship CPUs, mobos, coolers, RAM, etc., which obviously would cover more modest parts.

You talk about USB4 - yet USB3 and even USB2 are still widely used - even on brand new boards and cases. For example, the ASUS PRIME Z790-A WIFI does not even have a single USB4 port.

Important to remember, USB-C is not the same thing as USB 4. That board has several USB C ports, but C defines the connector, not the protocol and those USB-C ports support USB 3.2, not USB-4.

Correct me if I'm wrong here but to add to what you said isn't also lowest man on the totem pole sets the power with these ports? So USB4 can provide up to 100w but I believe it has a minimum (too lazy to look it up) that's something like 10-15w. So the case or mobo can limit the amount the power as long as the port is within spec even if the add-on device can take more?