Power Supply Choices

[HeadHunter52]

I'm looking to upgrade my power supply to solve some cable issues and get ready for a GPU upgrade down the road. I've seen various ratings such as gold, bronze, etc...

 

After deciding on a power rating, how important is the energy rating system mentioned above? Realistically, do the higher ratings equate to measurable energy savings and reliability? What power supplies do you use?

[Priller]

You want to use the properly sized PSU for your application plus some headroom depending on future growth plans.

 

You dont want to put a 1000 watt PSU in a system that only needs 500 watts. You may see better efficiency using a smaller PSU.

 

Read this: https://en.wikipedia.org/wiki/80_Plus

 

I always use various load calculators then add 10-20% on top of what I may use in the future in regards to SLI/Crossfire. Gives plenty of room to add second GPU plus watercooling, fans, etc.

 

In terms of PSU manufacturers.

Seasonic (OEM for many brands)

Superflower(OEM for many brands)

 

These will often be self labeled and found in other "Brands" as well, such as Corsair and XFX.

 

Always check who actually makes the PSU and not just the name on the side and look for a review on the actual PSU you intend to purchase as it may have more ripple or lower efficiency then another PSU of the same or less price.

[Demon_]

agree

Edited August 10, 2015 by Demon_

[Cibit]

I use Enermax, Multiple 12v rails and modular:)

 

Never less than 850KW I have 1000 and 1200 KW in my 2 systems PSU only component I dont skimp on

[zaelu]

KW? Holly Molly... who's running the Flux Capacitor at full power here? :D

[outlawal2]

I have built a lot of systems for people as well as my own and I find that after painstakingly going thru all of the calculations and such, 9 out of 10 folks opt for a 700 or 750 watt PSU if they are gaming... In a typical system that is a bit of overkill but it does allow some headroom if you decide to put in a 2nd video card or whatever.. Also, running a slightly bigger PSU at a lower percentage is better than running a smaller one maxed out..

 

I have done the calculations many times and generally end up selecting a 700 or 750 for the reasons stated above...

 

Buy a name brand and like the other folks have said read some reviews as PSU's are NOT created equal.. (Bronze is fine for most applications)

[cichlidfan]

KW? Holly Molly... who's running the Flux Capacitor at full power here? :D

 

Now the neighbors know why their lights dim every now and then. :P

 

EDIT: I am running Corsair AX series in my machines.

Edited August 7, 2015 by cichlidfan

[Lucky]

I have the Corsair HX850i fully modular PSU. It powers everything in my rig. See my sig below.

[Art-J]

I've got a "cheaper" Seasonic in the form of an XFX. Love the stable 12V line, but a word of warning - it's damn noisy under load, a couple of times noisier than 5 remaining fans in my PC altogether. Not a big deal if You're a headphones-only user like me, but a show-stopper if You're crazy about silent builds.

[Abburo]

Energy rating says up to what power level the PSU have a stable output. I

am using a power source and I am almost reaching that rating level. In that moment the capacitors are starting to whistle :). That is not a good sign but it is working like this since 2 years ago with no issues.

[Cibit]

KW? Holly Molly... who's running the Flux Capacitor at full power here? :D

 

Ooops obviously it's watts ;)

[xxJohnxx]

After I ran into PC problems, possibly beeing related to PSU power issues with a 750W unit, I went for the Corsair AX1200i.

It has plenty of power to drive my setup, including dual graphic-cards and a custom water cooling system.

Also, under normal conditions it is silent, as the fan will only turn on if the load exceeds 50%.

[wasyl00]

Or if you're interested you can calculate amount the power you need for your system using THIS website. I would really not recommend buying overkill, waste of money. PSU are usually most efficient around 80-90% of the max load. It’s better to invest in higher quality one.

Edited August 8, 2015 by wasyl00

[Dusty Rhodes]

There is no such thing as OVERKILL on the PSU. Remember, with a PSU, you can play it forward with subsequent upgrades and such. Buy BIG now and you won't have to buy for years and upgrades later, plus you will have no doubt that the PSU might be a problem. 1000 Watts and you are good for years.

[HeadHunter52]

Thanks, guys. I believe I'm going for a 750w. I'll check reviews (stars) around the net for reliability and other items. I appreciate the feedback.

[BitMaster]

my PSU fan never switches on... :)

 

50% load and headroom, ultra stable OC, SLI ready. 7 years warranty too

 

Corsair AXi

 

btw, max wattage gaming with all OC'ed is roughly 550Watts with the setup from sig.

[Brisse]

There is no such thing as OVERKILL on the PSU. Remember, with a PSU, you can play it forward with subsequent upgrades and such. Buy BIG now and you won't have to buy for years and upgrades later, plus you will have no doubt that the PSU might be a problem. 1000 Watts and you are good for years.

 

As an engineer I would have to disagree. By going overkill, you get worse efficiency. Sure, the PSU might have a high efficiency rating, but the efficiency varies depending on the load (high in the middle, drops off at the extreme ends), and if you buy a very large PSU for a not so power hungry computer, you will end up running the PSU at very low load which hurts efficiency and wastes electricity and money unnecessarily.

 

Future PC components will only become more and more energy efficient and if you buy a 1000W PSU today, chances are that it will just be even more overkill for your next PC. I would only recommend 1000W for PC's with multiple graphics cards, never for use with a single graphics card. The best thing is to calculate the needs for every individual PC build though, so that you end up running the PSU at loads where it runs most efficiently. It's really not that hard to do, and if someone doesn't know the math themselves, then there are numerous websites that will do it for you. This is one of my favourites: http://powersupplycalculator.net/

Edited September 22, 2015 by Brisse

[Demon_]

Totally agree with Brisse. A psu should run in the range of his max efficiency (50%-80% of his max power). But at only 50%, it's a waste of money.

 

I'm too lazy to calculate: http://www.realhardtechx.com/index_archivos/Page362.htm

 

If your pc need 350w (one video card) to run, your psu (bronze certification) will generate 62w of heat. 350x100/85

If your pc need 550w (two video cards) to run, your psu (bronze certification) will generate 97w of heat in the small box.

If your pc need 550w (two video cards) to run, your psu (gold certification) will generate 61w of heat.

 

Looking for quality? http://www.tomshardware.com/reviews/power-supply-psu-brands,3762.html

Psu with "All Japanese 105°C capacitors". Seasonic (they made the XFX, Corsair AX series (not the 1200w)) or Super Flower are the best.

 

Easy hein? http://www.plugloadsolutions.com/80PlusPowerSupplies.aspx

Edited September 22, 2015 by Demon_

[sobek]

You dont want to put a 1000 watt PSU in a system that only needs 500 watts. You may see better efficiency using a smaller PSU.

 

Read this: https://en.wikipedia.org/wiki/80_Plus

 

This is a bad way to go about it. Switched power supplies are most efficient at 50% load.

[Brisse]

This is a bad way to go about it. Switched power supplies are most efficient at 50% load.

 

One just has to remember though, that a PC almost never runs at it's full theoretical load, even during demanding gaming sessions. Because of this, it is better to make sure that your average load is around the 50% mark, not the full load.

 

Example:

We have a PC that draws 500W at full load.

Realistically this is only going to draw 350-450W average during gaming, with peaks towards 500W. (a lot of people don't know this, or simply ignore because they don't fully understand it's consequences)

If one thinks that you should have a PSU that runs at 50% of max load, then you are going to end up with a 1000W PSU. In reality, this is 200W more than the most efficient choice, which is more like 400W*2=800W.

[Demon_]

Because no pc components run at full load all the time, all together.

Max power has nothing to do with efficiency. :thumbup:

 

 

PS: And don't forget to calculate 5w (idle when gaming) for the sata DVD drive.

Edited September 22, 2015 by Demon_

[Brisse]

And don't forget to think about the efficiency during those long sessions when your PC is idling or close to idling, such as when browsing the web. PSU efficiency plummets at low load (with a break point usually somewhere between 10-20% of full load). A modern PC may be idling at 50-125W and with a PSU rated at 1000W or more, you can easily end up with a PC that idles below that break point where efficiency plummets. If you make this mistake, your PC may very well end up drawing twice as much from the wall socket than necessary during idle. Most PC's spend a lot of time idling, so this is not insignificant.

[BitMaster]

you might be right with a non AXi PSU, with this switched thing, like sobek says, it is different.

 

My minimum draw is 145watts idle desktop with eff. above silver or gold, but this PC is made for gaming and there are sessions of 8-10h non-stop gaming and that is where the 500-550W will be drawn all the time ( as I can see in the Corsair SW ).

 

I plan on SLI so I will need 800W total, having 400 reserve for stability as I also overclock as far as it goes stable, it aint done without a purpose :)

[Brisse]

you might be right with a non AXi PSU, with this switched thing, like sobek says, it is different.

 

Almost every PSU on the market, including really cheap ones, are of the switched-mode type. It's been like that for at least a decade. You can assume that anything I have been writing applies to switched-mode power supplies.

 

My minimum draw is 145watts idle desktop with eff. above silver or gold, but this PC is made for gaming and there are sessions of 8-10h non-stop gaming and that is where the 500-550W will be drawn all the time ( as I can see in the Corsair SW ).

 

The 80+ certification only looks at loads between 20 - 100%. It doesn't tell us anything about the efficiency below 20%, which in your case with the AXi1200 is 240W.

 

If your idle is 145W, then you are below the break point where the efficiency of your power supply goes down.

 

 

I plan on SLI so I will need 800W total, having 400 reserve for stability as I also overclock as far as it goes stable, it aint done without a purpose :)

 

With 800W I'm pretty sure you already have overclocking headroom even for a machine with two powerful graphics cards.

[Bucic]

If you buy a highier tier 80 Plus PSU you can load it up to 90% + for hours a week and it's not going to cause any problems. A 400 W CAN handle a GF660Ti and an overclocked 100+W 4+ GHz CPU just fine.