quiet 700+ watt PSU?

afireinside · Post by **afireinside** » Tue Mar 16, 2010 12:52 am

My 750w coolermaster real power pro is by far the loudest part of my computer. It's not THAT loud with a single 5770 right now but it was a lot worse with my GTX 260 and I'll soon have THREE 5770s. Is there anything out there that's silent and capable of powering:

3.8ghz 1.63v phenom 2 quad
3x 5770 overclocked

andyb · Post by **andyb** » Tue Mar 16, 2010 7:17 am

Where did you get the 700W number from.?

Seems a bit high even for a system with 3x graphics cards.

Here is the actual power consumption of the 5750, and for comparison the 5850 lets call it 100W per card, add your CPU 140W (for the most power hungry chip AMD have ever released) 10 W for RAM, 10W per HDD say 4x = 40W, 10W for the ODD, 10W for fans, 30W for motherboard and onboard components.

Graphics cards 300W.
CPU 140W.
RAM 10W.
HDD's 40W.
ODD 10W.
Fans 10W.
Mobo 30W.

Total: 540W and I have over-egged that cake by 100W I guess.

Here is a list of PSU's that have been tested by SPCR and are very good.

http://www.silentpcreview.com/article986-page5.html

this is by no means comprehensive, and there are usually lower power models to each of the ones tested.

FYI, My home server has 9x HDD's a hardware RAID card, an 89W CPU and doesn not get close to the 325W Enermax xxxxx 82+ PSU that is powering it.

Andy

afireinside · Post by **afireinside** » Tue Mar 16, 2010 9:16 am

my CPU pulls a lot more than 140w with its overclock. At much lower voltages on the CPU with two 4850s I was pulling around 500 watts at the wall in some cases. I'm sure I won't use 700 watts but I'd like a good bit of head room and I can't imagine any PSU being quiet when nearing 100% load.

andyb · Post by **andyb** » Tue Mar 16, 2010 2:11 pm

my CPU pulls a lot more than 140w with its overclock. At much lower voltages on the CPU with two 4850s I was pulling around 500 watts at the wall in some cases.

Still not a problem, 500W at the wall @ 80% efficiency is 400W of PSU output.

PSU's power rating is at the output not at the wall, theoretically you could have a machine sucking 1,000W at the wall, but because the PSU is only 50% efficient the machine is only using 500W.

Its nice to have some headroom, but spending cash to have a PSU that gives you 300W of headroom is crazy, at absolute most you need 100W to be perfectly safe from possible power usage spikes. Remember that quality PSU's can and will sit at 100% load without an issue in the short term (hours/days), running a PSU @ 90% for years is not an unreasonable thing to do so long as it is not overheating. Whats more important is the quality, power efficiency, price and warranty.

Andy

swivelguy2 · Post by **swivelguy2** » Tue Mar 16, 2010 2:18 pm

Try a Seasonic X-750 perhaps?

afireinside · Post by **afireinside** » Tue Mar 16, 2010 4:05 pm

andyb wrote:
my CPU pulls a lot more than 140w with its overclock. At much lower voltages on the CPU with two 4850s I was pulling around 500 watts at the wall in some cases.
Still not a problem, 500W at the wall @ 80% efficiency is 400W of PSU output.

PSU's power rating is at the output not at the wall, theoretically you could have a machine sucking 1,000W at the wall, but because the PSU is only 50% efficient the machine is only using 500W.

Its nice to have some headroom, but spending cash to have a PSU that gives you 300W of headroom is crazy, at absolute most you need 100W to be perfectly safe from possible power usage spikes. Remember that quality PSU's can and will sit at 100% load without an issue in the short term (hours/days), running a PSU @ 90% for years is not an unreasonable thing to do so long as it is not overheating. Whats more important is the quality, power efficiency, price and warranty.

Andy

I'm aware of that, but I've never had a heavily loaded PSU be quiet. I figured a PSU with lots of headroom would be quieter than one under heavy load. All my fans are yate loons at around 700RPM so I'm pretty picky with noise.

andyb · Post by **andyb** » Wed Mar 17, 2010 5:32 am

I figured a PSU with lots of headroom would be quieter than one under heavy load. All my fans are yate loons at around 700RPM so I'm pretty picky with noise.

Not according to the SPCR link I posted, at 400W the 430W Nexus is the quietest PSU, the rest of them are all over the place. As SPCR have demonstrated having a PSU with its own airflow and seperate from the rest of the system makes a huge difference (how much depends on the PSU of course), this is going to make a bigger difference than a way over powered PSU - and as you already have a P182 any PSU you use wont ramp up the fan as much.

Andy

afireinside · Post by **afireinside** » Wed Mar 17, 2010 9:57 am

andyb wrote:
I figured a PSU with lots of headroom would be quieter than one under heavy load. All my fans are yate loons at around 700RPM so I'm pretty picky with noise.
Not according to the SPCR link I posted, at 400W the 430W Nexus is the quietest PSU, the rest of them are all over the place. As SPCR have demonstrated having a PSU with its own airflow and seperate from the rest of the system makes a huge difference (how much depends on the PSU of course), this is going to make a bigger difference than a way over powered PSU - and as you already have a P182 any PSU you use wont ramp up the fan as much.

Andy

Mine ramps up the fan big time. It has the bottom chamber 100% sealed off from the top all to its self.

lodestar · Post by **lodestar** » Wed Mar 17, 2010 3:24 pm

The issue here I think is indeed power draw. The Phenom when overclocked is famous/infamous for being quite a power hog, so the question I ask is why are you overclocking? Overclocking can be worth it if you are gaming at resolutions at around 1680x1050 or lower. At higher resolutions it makes little or no difference, and is just a waste of power. I would assume that anyone that uses two cards CrossFired, and is considering going triple CrossFire (and overclocked graphics cards at that) would be running at a res of at least 1920x1200 or 1080p. If you are not you should be. Try running the CPU at stock settings and see what difference it makes.

Edit: Don't take my word for it. This review of your CPU at stock and 3.8 Ghz settings shows that the effect of overclocking at higher resolutions is zero http://www.neoseeker.com/Articles/Hardw ... ii/15.html. The same review shows that overclocking to that level increases overall system power consumption by 120w http://www.neoseeker.com/Articles/Hardw ... ii/18.html.

However this does not answer your original question which is how can you power three overclocked gpus in crossfire with CPU overclocking quietly. And the important word here is quietly. Most PSUs (with the notable exception of the Nexus 430 Value) have a sweet spot in terms of both quietness and efficiency at around 50% of nominal capacity.

If you stick with overclocking I suspect that with a single graphics card your system power consumption is at least 350w, rising to around 550w for three cards, taking account of using overclocked graphics cards. So a quiet PSU would be at least 1100w capacity, and it seems to me that you would need to look at something like the 1250W Enermax Revolution85+. If you stop overclocking then you could drop down to something like the 1050W Enermax Revolution85+. Yes, expensive. Yes, over-specified. But if you really want a quiet PSU this is the only way to go.

afireinside · Post by **afireinside** » Wed Mar 17, 2010 10:22 pm

http://www.legionhardware.com/articles_ ... 970,1.html

I'm gaming at 1080p. Even if it didn't help gaming performance (and it does) I'd overclock anyway. I refuse to run stock. Where's the fun in that?

Had a feeling I'd need something massive for silence

PlanetOfTheApes · Post by **PlanetOfTheApes** » Wed Mar 17, 2010 10:46 pm

What about 2 x Silverstone ST45NF load sharing in a case that supports dual ATX PSUs such as CoolerMaster ATCS 840, Silverstone TJ07, etc. Doesn't get any better than this noise wise.

I was looking at some of your early post and it looks like you're mounting the radiator in the P182's lower chamber. I wouldn't be happy with this arrangement. You may need to rethink the radiator placement. A more suitable case may help in this regard.

lodestar · Post by **lodestar** » Wed Mar 17, 2010 11:34 pm

afireinside wrote:Had a feeling I'd need something massive for silence

Thought so, see http://www.jonnyguru.com/modules.php?na ... y&reid=145.

Edit: And if you really want one, http://www.quietpcusa.com/Enermax-Galax ... 567C0.aspx but the clock is ticking on that mail in rebate.

afireinside · Post by **afireinside** » Thu Mar 18, 2010 8:05 am

PlanetOfTheApes wrote:What about 2 x Silverstone ST45NF load sharing in a case that supports dual ATX PSUs such as CoolerMaster ATCS 840, Silverstone TJ07, etc. Doesn't get any better than this noise wise.

I was looking at some of your early post and it looks like you're mounting the radiator in the P182's lower chamber. I wouldn't be happy with this arrangement. You may need to rethink the radiator placement. A more suitable case may help in this regard.

Not buying a new case. Radiator is being upgraded to an MCR420 and mounted externally behind the case.

SebRad · Post by **SebRad** » Thu Mar 18, 2010 9:19 am

I suggest Antec CP-850 PSU as it will fit P182. Unique 120mm fan straight-through design gave good results when SPCR tested it. Also maintained reasonable noise level even at 700w output when wasn't in the "hot box", I.E. like when the P182 seperated from rest of the system.

Zalmans 1000w heatpipe equiped PSU is also good when faced with high power loads.
Otherwise I guess Seasonic X-750 is probably about as good as it gets.
Seb

afireinside · Post by **afireinside** » Thu Mar 18, 2010 10:05 pm

SebRad wrote:I suggest Antec CP-850 PSU as it will fit P182. Unique 120mm fan straight-through design gave good results when SPCR tested it. Also maintained reasonable noise level even at 700w output when wasn't in the "hot box", I.E. like when the P182 seperated from rest of the system.

Zalmans 1000w heatpipe equiped PSU is also good when faced with high power loads.
Otherwise I guess Seasonic X-750 is probably about as good as it gets.
Seb

Didn't even think to stuff a CP-850 down there. Cheap to. Problem solved. Thanks a bunch!