This is a repost from this thread over in FSP support that hardly anyone saw and no one replied to.
Hello, I am looking for a PSU recommendation, but I need the PSU fan to run and extract air from the case as well as cooling itself.
I have a Silverstone SG01 case that I am planning to build up into a system in the new year. From the picture below (of the back of the case), you can see that the motherboard goes at the base of the case, with the power supply above it and directly over the CPU.
Thinking about how best to cool the system, I think that it would be best if I arranged for air to enter via the vents in the sides, the CPU fan to be reversed so as to push that air upwards into the PSU, and then the PSU fan to extract the air through the PSU and out of the case. For that to work the PSU fan would have to run continuously and not shut down when the PSU internals are cool enough. If the PSU has a thermostat switch that I can set to a low temperature then that would do the trick, alternatively I could use a PSU without a temperature sensitive cooling feature or one where it could be switched off.
I realise that I could open the PSU and mod it to connect the fan directly to a 12 volt rail, but I would prefer not to void the warranty on a brand new PSU.
I know that when the ATX specification was original defined, it was normal for the PSU to contain the only cooling fan on a case, and for that reason the PSU was often placed directly over the CPU so that it draw hot air directly from it and out of the case. I also know that in the 10 years since then the heat output of CPUs has drastically increased, and PSU builders have fitted temperature sensitive fans, that only go on when the PSU temp rises above a fairly high threshold.
As for the rest of the PSU spec, something in the 400-600W range would be good, as would high efficiency and modular connectors. Obviously there need to be vents on the bottom of the PSU, and preferably a big 120mm fan.
Any ideas? Thanks.