I wanted to get it as cheap so what I did was using a Nactua NF-R8 in place of the fan used in the cheap PSU currently installed. Connected without as attenuator adapter, it was actually quite noisy ! not what I expected. So I now use the red wire between it's voltage connector and the 12v rail, and getting reasonable quietness, fan running at 1300rpm. Will of course monitor the PSU heat, if too hot will get a new PSU for the job ;)
I also installed an Arctic Cooling Freezer 11 LP (low profile 92mm) which so far is very quite and keeps the Q8200 Core2 Quad at 40c-45c with fan speed varying between 600rpm-1000rpm.
Not sure about what to use as intake fan as, as I said, the NF-8R at full speed is not quiet. Will running it ULNA (800rpm) be good enough ? as I said it is not a gaming machine, but quite standard.
I also found that there's a dedicated place for a 120mm fan on the left cover, so I wonder if it would be ok to use that one instead of the rear 80mm fan.
If you put a fan on the left cover, make sure the rpm is slow. A general principle is that fans on the rear will be quieter because of the rear location, while fans on the front or side will be noisier because of the more direct path to your ears. Front fans obstructed by filters or fascia structure could be somewhat quietened, making side fans directly on the cover potentially the noisiest location. In addition, mounted on the thin metal of a cheaper case, a side fan can make the entire side cover vibrate and transmit noise. If you do put a fan there, see if you can attach some kind of heavy lining on the inside of that cover.
Thanks for the suggestion.
I meanwhile managed to get another NF-R8 to use as intake. Connected with no resistor RPM attenuator, it spins at about 700rpm (very silent). Is the motherboard able to control the fan speed with no PWM ? (the P5Q has 3 prone jacks for the chassis fans)... Just wondering ;)
I will get just about another NF-R8 for the exhaust. So far so good ! ;)
Before buying your PC, you should check out CPU/Processor of your computer. Whenever, it gets heated then fan automatically speeds up to make processor/CPU cool..
My PC now runs almost totally quiet with a NF-R8@800rpm as intake, No-brand 80mm@800rpm as exahust and an NF-R8@1000rpm as PSU fan. CPU cooler is Arctic Cooler Freezer LP 11.
CPU temp runs 38-47C at max, and ambient temp of about 40C. The PSU is a bit warm but doesn't feel too hot for a power supply...