jonnyGURUSee, this is a perpetuation of a misconception.

AC not converted to DC is converted to heat. If the PSU is more efficient, it generates less heat. If you have two PSUs with the same efficiency at the same load and one has hotter exhaust than the other, that is not because on PSU is running hotter than the other. It's because it's better at moving the heat AWAY from the PSU. Whether it's because of the fan design or PCB layout.

When I was at BFG, we designed a PSU with the components set perpendicular to the main PCB as opposed to putting them on the main CPB itself. This allowed the air to flow across the components instead of just "pushing air down" onto the tops of the components. The results was very low internal temperatures, but higher exhaust temperatures. Why? Well... the heat has to go somewhere and if it isn't, then you're cooking your components!

So what does Paul at HardOCP say? "Con: Exhaust temperatures very high."

THIS is how you do a proper thermal test:


It's NOT done by just measuring the delta between intake and exhaust temperatures.

Stuff like that is hard to hear :(

If you have a heatsink or collection of heatsinks dissipating 50W of waste heat to air, the temperature of the exhaust is entirely dependent on the speed of the exhaust airflow. Heat is energy per unit of mass or volume, so to criticise a PSU for high output temperatures is just demonstrating ignorance of basic physics. Nobody with that lack of basic understanding should be making judgements in reviews.

You know how to get exhaust temperatures down? Run your fan at an unpleasant, deafening speed. Now the PSU is a horrible piece of unbearable trash but hey, aT LeAsT tHe ExHaUsT tEmPs ArE LoWeR LoL

Unfortunately forums and sites are often chock full of people who lack a basic grasp of high-school physics, but have plenty of energy to argue and dispute other people's posts. Arguing with an idiot who is too dumb to understand that they are dumb is an exercise in frustration and futulity. Thankfully there's an ignore button on TPU so the trolls and people who can't even accept basic math or phsyics can be silenced (for me, at least).

The exhaust argument is so bizzare to me. It’s been known for a long time in my circles at least that, for example, a well ventilated build will pump out far more hot air into the room than a poorly ventilated one. That’s just basics. Arguing for lower exhaust temperatures on PSUs seems nonsensical. I mean, what, do you WANT the hot air to stay inside? I mean, shiiiiet, lemme just run a case without any fans whatsoever, should have no hot exhaust at all. Seems like a brilliant idea. Saves money too. BRB, gonna screw out all the fans from inside my Torrent.

OnasiThe exhaust argument is so bizzare to me. It’s been known for a long time in my circles at least that, for example, a well ventilated build will pump out far more hot air into the room than a poorly ventilated one. That’s just basics. Arguing for lower exhaust temperatures on PSUs seems nonsensical. I mean, what, do you WANT the hot air to stay inside? I mean, shiiiiet, lemme just run a case without any fans whatsoever, should have no hot exhaust at all. Seems like a brilliant idea. Saves money too. BRB, gonna screw out all the fans from inside my Torrent.

If a PC uses 300W, the amount of energy it pumps into a room is 300W, regardless of fan speed or cooling efficiency (because 99.9999% of the energy a PC uses is converted to heat - sound and light are very very very low-energy by comparison)

The temperature of that airflow depends on the rate of airflow. 300W dissipated into a small amount of air (low rate of airflow) will inevitably produce higher exhaust air temperatures, but higher temperatures at a lower rate is the same amount of energy per second being dumped into the room. That's the energy conservation law.

@Chrispy_
Guess I phrased that poorly. What I am talking about is subjective human perception here, not physics. Which you have indeed described correctly. I definitely feel the exhaust heat out from my Torrent far more than from my old Define S, even though they both houses the exact same components. The Torrent is just far more effective at removing the hot air from the case. The Define was slower and subjectively it FELT like it wasn’t breathing out as much heat, even though objectively, of course, it was. The Torrent both has more fans and a freer exhaust area in the back, which IS noticeable.

Onasi@Chrispy_
Guess I phrased that poorly. What I am talking about is subjective human perception here, not physics. Which you have indeed described correctly. I definitely feel the exhaust heat out from my Torrent far more than from my old Define S, even though they both houses the exact same components. The Torrent is just far more effective at removing the hot air from the case. The Define was slower and subjectively it FELT like it wasn’t breathing out as much heat, even though objectively, of course, it was. The Torrent both has more fans and a freer exhaust area in the back, which IS noticeable.

The temperature you feel, sitting near your PC is more down to where warm air is going. Sitting in a room with a heat source (PC case), the average temperature of the room isn't likely to be the same as the local temperate where you are sitting. Something as simple as orientation of the PC case, or more airflow from the Torrent stirring up the air near you more effectively, so mixing the warm exhaust with the cooler air in your vicinity to make it feel warmer.

Without knowing your past and present room/desk setup, I'm guessing that the old Define resulted in less disturbance in the room airflow, so the warmer air stayed closer to the PC and wasn't reaching you as effectively. Like you say - it's subjective perception and the physics behind the energy dissipation of the same parts cannot lie.

jonnyGURUIf you're living in some alternate universe where wrong is right... I have no time for you.

People with more objective opinions are welcome.

You are the reason my last PSU I bought was a Corsair, I trust your expertise, consulting, and quality control influence on Corsair PSU's! Keep up the good work and ignore the haters.

jonnyGURUBecause websites are supposed to be profitable. If you pay Aris what he's worth, there's no money left for the profitability of the website. ;-)

Can't argue with that logic really. But I meant more like multiple sites merely "licensing" the use of his content, not paying him to be on staff. Clearly sites can't really afford him which I'm sure is relevant to the fact that he's no longer writing for TH or this site anymore.

darkbreezeCan't argue with that logic really. But I meant more like multiple sites merely "licensing" the use of his content, not paying him to be on staff. Clearly sites can't really afford him which I'm sure is relevant to the fact that he's no longer writing for TH or this site anymore.

they don't license his work, they own it otherwise they would need to take it down or pay a licensee fee each time it was up. Reviewers are simply contract work for the site

dirtyferretthey don't license his work, they own it otherwise they would need to take it down or pay a licensee fee each time it was up. Reviewers are simply contract work for the site

Yes, I know how it works. I was simply suggesting an alternate method that could benefit both Aris and any site that wanted to be able to use his review data on their site. And no, not all reviewers are contract piece workers. Many of them are full time staff depending on the site.

Beginner Macro DeviceTrue that. Fortunately idgaf about the noise so my fans roar and temps stay sane or even low for, like, 99.9% of the time. That's why my PSUs and other electronics live for much longer than they are relevant performance/feature wise.

Thing is, those push pull 80s don't have to be loud and will cool much better. But customer perception is so distorted now.....

chrcolukIronically the silent mode on my PSU made a weird noise, I guess is a defect on it somewhere so I enabled normal mode to shut it up, and its never made any kind of noise that I can hear over the rest of the PC.

You have a PSU with a "silent" and "normal" mode?

Chrispy_Unfortunately forums and sites are often chock full of people who lack a basic grasp of high-school physics, but have plenty of energy to argue and dispute other people's posts

The world is full of people who lack a basic understanding of high school math, science, and literature. Forums are simply a place for those people to congregate and prove their lack of understanding on daily basis.

darkbreezeMany of them are full time staff depending on the site

:kookoo: I'll give you three guesses which site we are talking about. Don't cheat and look at the thread title.

jonnyGURUThing is, those push pull 80s don't have to be loud and will cool much better. But customer perception is so distorted now.....


You have a PSU with a "silent" and "normal" mode?

Yes, I run it in normal mode.

jonnyGURUThing is, those push pull 80s don't have to be loud and will cool much better. But customer perception is so distorted now.....

Amazing; I had no idea.

pk67Hot spots at bridges telling us this one design asking for some changes:laugh:.

Hot semi-conductors are more efficient, so a designer might intentionally avoid putting a heat-sink on a rectifier bridge.

jonnyGURUAnd while this may work for most, I still feel a lot of information is lost not only on the end user... but also the reviewer!

We(consumers) do not care for most laptop or phone chargers while it is basically the same device, even more it is passive and more cramped. Why are ATX PSU so special? We look for compatibility chart and that is it. It should be same, no hard feelings.

But we(engineers) usually overdo and bring our technical beef from prototyping phase, maxing out current platform, well unlike other products, you still know your prototype can work, imagine designing product and debugging it for 3 months with new silicon, pulling hair and then errata comes, hey it was a CPU bug..., but let us leave it there, no one cares about the internal struggles. I don't give a damn about review remarks about part origins, hot exhaust etc, as long the price/performance is fine. Warranty covers every other aspect. Here we have a reviewer for mice that puts slow charging as negative for 200mAh cells, I am not sure what does he expect putting than more than 1C into them or thicker wires are for higher frequencies... OK enough with the sad jokes. I rarely venture into audio related stuff also, I read only reviews done by Amirm, he does plots, it is enough, very limited comments, he crates a basic datasheet. Basically I do not even expect high precision review, not needed, no review will catch that my older Corsair AX850 will melt their pcie 8pin connector and wires after 3 years either way, you have to put moving air there, sure, my fault, but it can also be solved with a better PCB, case design and FAN shroud, maybe another type of wiring pinouts(s).

Same applies to any job, reviews are time consuming, but you have to go down to earth and look at these things from client perspective, we do not need useless data in our busy lives, we do read the conlusion mostly, I like to look at pictures also, but because I understand the design, if I see crap factory soldering, then okay, no thanks, but component quality? Lottery with humming coils? How a review will cover that? Contrary I simply do not understand some reviewers not measuring some distances, put a ruler besides the connectors or make detailed drawing, that is crucial, especially for small form factor builds. You can add usefull info without any hassle. You cannot imagine how many beers I owe to W1zzard as he does high resoltion PCB shots on his reviewed GPUs. Putting schematics like it was a norm in early days is no fashion anymore, but I would like it to be enforced by law. But the technical bits, with high end equipment, that never will pay off and it is not needed. We need a ATX PASS badge and compatibility list, and cosmetics, dimensions, accessories, fan modes also must be clearly explained in the included manual, another bullshit badge, what does mean noise level A+ or A++ mean? After 50ies age or before? Or after serving military or not? Last time I looked those things are still measured in decibels, just put plots, at current X we have dB Y. We download component datasheet, those like are like cornerstone of everything and they look and work fine. PSU should have such datasheet included in the first place and if not the review should emulate it. Not all of it, but mechanical and basic stuff is enough for a review.

To be fair. How many revisions of the same marketing named device you have? Changing fans, their curves. EU/US version differences, then parts change as those run out of stock... so how revelant the detailed PSU review even remains? I mentioned laptop chargers, they are multi sourced, while they look similar outside they are shuffled, even laptop fans differ, some have like 5 versions, due to minimizing supply chain risks. Does the review cover all of them? Nope. Those are different designs, so overdoing it does not make sense either way.

Ferrum MasterWe(consumers) do not care for most laptop or phone chargers while it is basically the same device, even more it is passive and more cramped. Why are ATX PSU so special? We look for compatibility chart and that is it. It should be same, no hard feelings.

But we(engineers) usually overdo and bring our technical beef from prototyping phase, maxing out current platform, well unlike other products, you still know your prototype can work, imagine designing product and debugging it for 3 months with new silicon, pulling hair and then errata comes, hey it was a CPU bug..., but let us leave it there, no one cares about the internal struggles. I don't give a damn about review remarks about part origins, hot exhaust etc, as long the price/performance is fine. Warranty covers every other aspect. Here we have a reviewer for mice that puts slow charging as negative for 200mAh cells, I am not sure what does he expect putting than more than 1C into them or thicker wires are for higher frequencies... OK enough with the sad jokes. I rarely venture into audio related stuff also, I read only reviews done by Amirm, he does plots, it is enough, very limited comments, he crates a basic datasheet. Basically I do not even expect high precision review, not needed, no review will catch that my older Corsair AX850 will melt their pcie 8pin connector and wires after 3 years either way, you have to put moving air there, sure, my fault, but it can also be solved with a better PCB, case design and FAN shroud, maybe another type of wiring pinouts(s).

Same applies to any job, reviews are time consuming, but you have to go down to earth and look at these things from client perspective, we do not need useless data in our busy lives, we do read the conlusion mostly, I like to look at pictures also, but because I understand the design, if I see crap factory soldering, then okay, no thanks, but component quality? Lottery with humming coils? How a review will cover that? Contrary I simply do not understand some reviewers not measuring some distances, put a ruler besides the connectors or make detailed drawing, that is crucial, especially for small form factor builds. You can add usefull info without any hassle. You cannot imagine how many beers I owe to W1zzard as he does high resoltion PCB shots on his reviewed GPUs. Putting schematics like it was a norm in early days is no fashion anymore, but I would like it to be enforced by law. But the technical bits, with high end equipment, that never will pay off and it is not needed. We need a ATX PASS badge and compatibility list, and cosmetics, dimensions, accessories, fan modes also must be clearly explained in the included manual, another bullshit badge, what does mean noise level A+ or A++ mean? After 50ies age or before? Or after serving military or not? Last time I looked those things are still measured in decibels, just put plots, at current X we have dB Y. We download component datasheet, those like are like cornerstone of everything and they look and work fine. PSU should have such datasheet included in the first place and if not the review should emulate it. Not all of it, but mechanical and basic stuff is enough for a review.

To be fair. How many revisions of the same marketing named device you have? Changing fans, their curves. EU/US version differences, then parts change as those run out of stock... so how revelant the detailed PSU review even remains? I mentioned laptop chargers, they are multi sourced, while they look similar outside they are shuffled, even laptop fans differ, some have like 5 versions, due to minimizing supply chain risks. Does the review cover all of them? Nope. Those are different designs, so overdoing it does not make sense either way.

Just to add my view as a now retired engineer, to the above excellent summary."Reviews" of consumer products apply literally to the actual item being reviewed and little else. BOM revisions, cost reductions , cynical product marketing etc. all ensure the product you buy may be different from the one reviewed. Fit, form, function and warranty are the only specs you need, with failure rate a bonus (as you'll never see that unless you have involvement). We don't need reviews and marketing fluff we need honest data/specifications - I don't buy things because other people tell me they're good, I buy because they fulfil a need.

DrashI don't buy things because other people tell me they're good, I buy because they fulfil a need.

I just shopped for a new washing machine and dryer, and most any would fulfil the need, but I wanted reliability and access to spare parts and that meant LG rather than Samsung.

ShrekI just shopped for a new washing machine and dryer, and most any would fulfil the need, but I wanted reliability and access to spare parts and that meant LG rather than Samsung.

Samsung - they were the one at the front of my mind when I wrote "BOM revisions, cost reductions , cynical product marketing", especially the last part. I don't have many shopping rules but "not Samsung" is probably my top!

Ferrum MasterWe(consumers) do not care for most laptop or phone chargers while it is basically the same device, even more it is passive and more cramped. Why are ATX PSU so special? We look for compatibility chart and that is it. It should be same, no hard feelings.

Are you sure laptop chargers are more cramped than pc PSU ???
If so try to count it once again. Divide Pout nominal by side surfeaces area in both cases to get estimared fair metrics, And keep in mind laptop chargers can be easy way (at low cost premium) oversized so thier efficiency is way higher at max load than efficiency gold or even platinium rated PSU at their max load.
edit
Also dust is not a problem for sealed laptop chargers. They can work fine long after their warranty period expired. You cant say the same about most of the desktop PSU-s ( if they must working at heavy load ).

ShrekHot semi-conductors are more efficient, so a designer might intentionally avoid putting a heat-sink on a rectifier bridge.

It is so stupid sentence I dont even have any motivation to comment it anymore. In some cases stupidity is just self explanatory i see.

pk67It is so stupid sentence I dont even have any motivation to comment it anymore. In some cases stupidity is just self explanatory i see.

Thermal energies make it easier to overcome the diode drop, and so increase efficiency.

voltage - Why does temperature modify the characteristics of a diode? - Electrical Engineering Stack Exchange



So, a hot diode has higher efficiency.

pk67Are you sure laptop chargers are more cramped than pc PSU ???
If so try to count it once again. Divide Pout nominal by side surfeaces area in both cases to get estimared fair metrics, And keep in mind laptop chargers can be easy way (at low cost premium) oversized so thier efficiency is way higher at max load than efficiency gold or even platinium rated PSU at theier mx load.

These guys are talking from a different market segment than what we're discussing, clearly. The investment in engineering and safety certification to change a BOM at a whim of a quality electronic product (I'll leave it generic like that) costs more than any cost savings. That said, there are a lot of products out there that don't have UL, TÜV, KCC, CCC, etc. and can change BOMs without recertification and since they only offer the legally required (for EU and other countries) two year warranty, don't care of the product goes boom on year three.

As for laptop bricks: They are more dense, but also more expensive. If you do the math, they are small square mm to a desktop PSU. But they're also filled with thermally inductive potting material and wrapped in an aluminum sheet for cooling, so a whole different approach has to be taken to thermals. And, of course, I'm only talking about the better bricks from Delta, Chicony, FSP, etc that have proper certs and don't change the BOM every three months to save a quarter and not the ones that sell on Amazon that only have "CE" for "China Export" that will only last just over a year.

ShrekI just shopped for a new washing machine and dryer, and most any would fulfil the need, but I wanted reliability and access to spare parts and that meant LG rather than Samsung.

As a tech with access to LG documentation and OEM spare part ordering, you did the right choice.
LG holds up to older design parts much longer, at least for now. For home appliance electronics I have nothing bad to say about LG.

pk67Are you sure laptop chargers are more cramped than pc PSU ???
If so try to count it once again. Divide Pout nominal by side surfeaces area in both cases to get estimared fair metrics, And keep in mind laptop chargers can be easy way (at low cost premium) oversized so thier efficiency is way higher at max load than efficiency gold or even platinium rated PSU at theier mx load.

Have looked into recent designs, you have to a hammer it to take it apart and scrape the thermal silicone. We have a 160W phone charger already, the 300W+ laptop supplies are very close in bom, keep in mind, those are passive designs. The ATX12VO should be more comparable. Fundamentally it has the same logical structure if we divide the added parallel devices needed for the additional power margin. But people simply don't care about those, ain't it? The barrel jack or type c fits, it works, and the consumer does not care about anything else.

Ferrum MasterHave looked into recent designs, you have to a hammer it to take it apart and scrape the thermal silicone. We have a 160W phone charger already, the 300W+ laptop supplies are very close in bom, keep in mind, those are passive designs. The ATX12VO should be more comparable. Fundamentally it has the same logical structure if we divide the added parallel devices needed for the additional power margin. But people simply don't care about those, ain't it? The barrel jack or type c fits, it works, and the consumer does not care about anything else.

Did you done calcs i asked you ?? No. Instead you are comparing aplles to oranges. Laptop chargers have typically way higer Vout than 12V in ATX standard.
So their Iout is way lower at the same Pout levels as for desktop PSU-s. :eek:

jonnyGURUBut they're also filled with thermally inductive potting material and wrapped in an aluminum sheet for cooling,

thermally conductive?

jonnyGURUthat only have "CE" for "China Export" that will only last just over a year.

:p

We are talking mass market comsumer gear aren't we? PC PSUs are extremely important (for a PC) but nonetheless they are low priced disposable consumer grade items. Some are better than others, but they're "just consumer". Any reviewer, unless not an "outsider", will just be giving an opinion on one unit. All you can realistically expect is a black box evaluation. A good test program with some nice gear to see what the reality is vs. the marketing wank - looking for spec non-conformance or an Achilles' heel that may upset a built system. Delving any deeper seems misplaced effort. Perhaps cover off visual inspection - build quality, gotchas, assembly quality. Is that a review or just 3rd party QC?

In a past role designing test and repair solutions for telecomms equipment (including multi-kW -48V BTS PSUs, Eltek, Emmerson, Nokia, Siemens etc.) we had access to field failure rates, failure modes and repaired and tested to manufacturers specs with defined KPIs. Black box is the only way to approach this - replace like with like, make good, test and verify - if it passed from previously being a charred dead wreck then job done. I'm not sure discussion of A vs B architecture or fan or component is needed. It's almost a pass/fail exercise.

ShrekThermal energies make it easier to overcome the diode drop, and so increase efficiency.

voltage - Why does temperature modify the characteristics of a diode? - Electrical Engineering Stack Exchange



So, a hot diode has higher efficiency.

Your attention is focused on wrong quadrant :roll:. Look at 3rd one ( anti clockwise counted) - you have way higher reverse current for hot diode. At almost two orders of magnitude higher reverse voltage. Sure - this part of loss is not as high as losses in first quadrant but they are going blatantly in opposite direction. And keep in mind real doiodes have their conductive connectors too. So total loss is a sum of few components. And their ohmic loss increasing for sure along the temperature rise.

Your blatantly stupid sentece was a wrong generalization for all hot semiconductors. You cant say the same about power mosfets for sure.
I'm too lazy to teaching you all rudiments here.