How hot do PSUs actually run?

StopNotWorking

I'm in a bit of a fluster over this

I have a corsair 750w PSU and the specs in my sig. Recently I was told I was a huge moron for thinking my PSU was exhausting anything other then the hottest air in my case. With that in mind I turned over my PSU(It was upside down) so the air was blowing out of the bottom hole in my case(Cooler master 590 comes with a 120mm exhaust hole under the PSU mount for this reason).

Since doing that my GPU(Which is directly above where the PSU used to exhaust) has jumped in idle temps from 41/43 to 49/51. Now I'm not sure what to think. The load temps on my graphics card is still the same(between 60-70 when playing games). Could anything else have caused this?

I just got a second monitor(1920x1080-24")I'm now running two screens, one 20" and the other is the above one. Could this be the cause of the higher temps?

Hopefully someone can clear this up for me, I've seen the specs on my PSU and many others and they state things like "Stable 750w at 50c" and the like. But the hottest thing in my computer has always been my gpu or cpu. I've had the case open before and checked with my hand where the hot air was coming from, and it was never from the psu..

marco_polo

A psu fan is an intake fan not an exhaust fan isn't it?

EDIT: No I think I am talking crap

StopNotWorking

Yeah as far as I know it's an exhaust fan. The intake is from the back of it(The grill where the plug goes).

marco_polo

StopNotWorking wrote: »

Yeah as far as I know it's an exhaust fan. The intake is from the back of it(The grill where the plug goes).

Wait a second, on those corsairs I think the fan is an intake fan on the top of the PSU and the Air flows out through the Grill on the back. So you were right the first time.

StopNotWorking

How has it gotten hotter then













I'll have to delve a little deeper into this when I get back from work

marco_polo

StopNotWorking wrote: »

How has it gotten hotter then













I'll have to delve a little deeper into this when I get back from work

Oh so the fan is pointing upwards at the gpu now?

EDIT: I completely missed the bit about the addition of dual screens, actually that that could very well account for a rise in tempratures.

StopNotWorking

The fan used to point upwards(towards the gpu) now its pointing down(out the hole in the botom of the case).

Stupid extra screen, first it won't fit on my table then it makes my computer hotter:rolleyes:

marco_polo

StopNotWorking wrote: »

The fan used to point upwards(towards the gpu) now its pointing down(out the hole in the botom of the case).

Stupid extra screen, first it won't fit on my table then it makes my computer hotter:rolleyes:

Ah I see now the fan takes air in so it when it was pointing upwards it would have been taking air away from the GPU and exhausting it through the PSU and out the grill at the back.

The answer is probably a little from column A and a little from column B.

See pic here:

http://www.phoronix.com/scan.php?page=article&item=926&num=3

StopNotWorking

Well with that in mind which do you think would be the better idea? Leave things as they are and let the GPU cook, or roll the PSU over and let the PSU cook..

marco_polo

StopNotWorking wrote: »

Well with that in mind which do you think would be the better idea? Leave things as they are and let the GPU cook, or roll the PSU over and let the PSU cook..

The PSU fan is supposed to extract air from the case as well so there is no worries I would turn it around.

I got muddled earlier as I would call the setup like the Corsair an intake fan from the PSUs point of view, whereas if the fan was towards the grill at the back I would call it an extractor fan. But from the perspective of the case airflow both types are basically an exhaust.

So confused I need to lie down now. .

StopNotWorking

Grr now you made me confused :mad:

I'll roll it over when I get home, thanks for the help marco(Obviously none of my B&U buddies want to talk to me anymore:()

marco_polo

StopNotWorking wrote: »

Grr now you made me confused :mad:

I'll roll it over when I get home, thanks for the help marco(Obviously none of my B&U buddies want to talk to me anymore:()

They must all be busy at work today unlike me

Solitaire

OI! Of course we still want to talk to you

AFAIK the days of PSUs venting hot air into the case are long gone. Almost all the newer models suck in hot air from the case and vent the even hotter result - its the reason that heat-derating became such an issue.

StopNotWorking

Right well I swapped it back over and sure enough the temps went back to ~40 at idle on the GPU. Lesson for anyone with a cooler master 590 and a corsair psu I guess, keep that upside down :pac:

Solitaire

The main reason to keep the PSU "right-side-up" in a modern bottom-loader case (thus taking air in from below the case) is if you have a hot-running PSU and a cool-running expansion area (if gaming the only way you'll have that is if you already have a ton of additional cooling over the GPU(s)). Otherwise the PSU can be better used to act as a nice little 140mm exhaust for the area and help prevent heat pooling around the GPU(s) - if the PSU is cool-running (Seasonic, Delta, CWT in particular) it can handle the extra heat itself and not add heat to the GPU(s); instead it will actually drop temps a bit. Plus, unless you have your case sitting on a ventilated stand mounting the PSU the other way around can actually strangle it as there isn't enough space under the case to support the pressure and airflow needed by the PSU

StopNotWorking

Solitaire wrote: »

Plus, unless you have your case sitting on a ventilated stand mounting the PSU the other way around can actually strangle it as there isn't enough space under the case to support the pressure and airflow needed by the PSU

Sounds like someone is speaking from experience there :pac: