Someone asked me this question in email yesterday, so I thought I'd answer him here since the early stuff always helps newcomers get started.
The question was the same one we've all heard, which PSU wattage rating to buy for my new system and how many drives can I run?
My answer from long ago, still seems semi-accurate:
Try using one of the free PSU calculators online to estimate your total system watts.
Here's a few to check out:
https://seasonic.com/wattage-calculator#
http://www.coolermaster.com/power-supply-calculator/
https://outervision.com/power-supply-calculator
https://www.bequiet.com/en/psucalculator
http://powersupplycalculator.net/
As far as calculating watts used per type of drive:
Search for the spec-data sheet for the HDDs drives brand and series and capacity you intend to use. Like this Seagate Barracuda PRO sheet below. It will tell you idle watts and load (operating) watts for each capacity of the drive series.
Do you plan on RAIDing the drives?
Will all your HDDs be running at once in a RAID array? or only a single drive, while the others remain idle?
https://www.seagate.com/www-content/...07US-en_US.pdf
A Seagate 12TB HDD uses 8watts at load according to the spec sheet. If you plan on using (10) HDDs at load all running simultaneously, that's still only 80watts.
My Samsung 860 Pro SATA SSDs use only 2watts at load, I have (4) total = 8watts
https://s3.ap-northeast-2.amazonaws....eet_Rev1_1.pdf
NVMe drives use a bit more power about 4 to 6watts per drive at load:
https://s3.ap-northeast-2.amazonaws....et_Rev.1.0.pdf
Intel Optane AIC PCIe SSDs can use up to 14watts at load:
https://www.mouser.com/pdfdocs/Optan...sDatasheet.pdf
1)
Calculating your total system watts from datasheets for all your individual components is going to be more accurate than using any of the PSU calculators listed above.
2) Although, I don't remember the last time I used either method, since I haven't built an entire system from all new components umm - ever. I've always used "simple incremental upgrades over time" since 2009 when I transferred parts from an old
Dell and built my first custom PC with a heatpipe cooled Zalman PSU and CoolerMaster Cosmos 1000, never an entire build at once. Who can afford that?
Simply adding one or two parts (mobo and CPU at the most)
to a system I already know the watts used at idle and various loads from reading a Kill A Watt meter early on and the last 5years APC battery backups that provide watts used as a digital display menu selection, so I already have an established watts used value and only need to add/change for the additional component(s), but I'm weird
.
3) A really good idea would be to build your basic system: platform only CPU mobo memory and O/S boot drive, CPU cooler either AIO pump and fans or good air, the fans alone, just the basics so you can boot,
using your current PSU, build it on the mobo box nice and clean and use one of these inexpensive Kill A Watt meters from
Amazon or anywhere for about $18. Then you can establish your baseline number "system watts needed" at idle and various load scenarios, and can decide from there how many HDDs SSDs you really want in your system, and all other additional components pwr consumption,
then decide which PSU is right for your new build. You can keep using the Kill A Watt meter for a single build, it will tell you the change in idle and gaming watts, working watts, O/S drive reformatting watts (writing to the drive) etc when you make additional upgrades, a nice tool to have around. (pic below)
4) If you're using your rig for work and find you really like knowing your watts pulled from the wall and want a battery backup as well from thunderstorms, brownouts, sometimes our power here will click off/on momentarily for no apparent reason, I don't want to lose my work, so I got into APC battery backup units about 5years ago, about 2013. The better models offer "Watts Used" for every device you have plugged into the unit, I've had three of the APC units, both with (6) or (8) power ports or outlets. I have both my rigs and a single display plugged into the APC battery backup, so to get an accurate reading of watts from either rig, I turn off the rig I'm not using, turn off the 27inch display and what's (watts
) left is power consumption of the system/rig I'm reading from the APC digital display. They can be costly, my first unit was an APC SMT 750VA about $275 (pic below). They last forever though, I never even changed the battery in that unit, kept it for 4.5years, sold it for $100, so total cost of ownership was $175 over 4.5years. Now I'm using the APC BR1000MS 1000VA about $148. Just make sure you choose an UPS with a pure sine wave output from battery, that's what the latest Active PFC power supplies need to continue working and for a clean and stable shutdown of your gear, if the power goes out.
It really just depends on how far you want to get into it. The Kill A Watt units work just fine, and only $18.