I recently assembled a PC in a full-size desktop case. The case as supplied had a 5cm extractor fan on the back, just behind the CPU/heatsink/fan assembly. It worked OK, but the fan was noisy, and - annoyingly - it obstructed one of the hard disk drive bays, so I couldn't install a second drive.

I removed the 5cm fan from the back, and installed an 8cm one at the front, sucking (blowing?) air into the case. I also blocked off most the holes on the back of the case, leaving just the fan hole behind the CPU.

There is now less fan noise, and the PC still works OK, but I've noticed that the air being blown out of the PSU is noticeably warmer than before - and it's warmer than the air coming out of the hole behind the processor.

Is this anything to worry about, and is there anything I can do about it? I did think of putting a baffle between the motherboard and PSU, to force most of the airflow over the CPU - would this help?

If you get hot air coming out through the back fan, I think it's not a bad thing Mike - if that fan weren't there, the hot air would still be in the case Although, having said that, you have blocked off a hole or two at the back where hot air may have escaped from previously which could be why you get even warmer air out the back of the PSU. If you want to improve airflow even more, you could fit a fan and dremel out any bits of metal which make holes. Most airflow noise comes from turbulence as things get in the way. If you leave it so you have a big hole rather than a pepper-dashed combination of little holes in a big-hole shape, that will improve flow and reduce noise.

I've recently upgraded my PC and fitted a pair of Panaflo 12cm fans. The bigger the fans you can get, the slower they can spin for a same airflow, therefore reducing noise. My PC is now pretty overclocked and has three hard drives in it, yet it's pretty quiet. OK, you can hear it, but you don't hear a protruding whining sound, so it's very bearable. The biggest amount of noise comes from the back fan and not the CPU fan. Although they're running at the same speed So I think I need to open up even more the venting hole at the back of my case (An Antec P160)

Mine is set up to suck inwards at the front and blow out the back, noisy but very cool (In the traditional sense)

Also might want to remove all of the PCI/AGP blanking plates as you can have more airflow this way too.

Currently have got a front case fan sucking in and rear fan blowing out - both 80mm fans. also have got an 80mm fan blowing onto an SL-97 thermalright heatsink which uses an elevated sink and pipes. think this helps because the cool air can be blown down and out because of the airgap at the bottom.

Do you have an extractor fan on the PSU too?

Suck at front, blow at rear (now where have I heard that before :naughty: )

Either way - the basic system is to get cool air flowing through the case. Most of the time pulling cool air in at the front (low) and blowing hot air out at the back (usually higher up) works well.

It is helpful to get hot air out before it hits the power supply, as most PSUs (esp. cheaper ones) cannot deliver their power ratings at higher temperatures.

Suck at front' date=' blow at rear (now where have I heard that before :naughty: )

[/quote']

Bangkok?

It's generally better also to have the same fan power sucking in as blowing out, so you don't have a pressure differential inside.

I have 1 x 80mm drawing in air at the bottom front, 2 x 80mm fans blowing out, one top and one bottom both rear, 1 x pci fan sucking air of the blown graphics card and blown out, and a 120mm fan blowing out from the psu, which also draws air up from the inside of the case.

Very ventillated yes, but not noisey.

It's generally better also to have the same fan power sucking in as blowing out, so you don't have a pressure differential inside.

I don't know, I've heard that as well but as long as the vents at the front are unobstructed I don't see much risk of a vacuum forming :P . If I disconnect the front fan and put my hand over the front vents I still feel a similar amount of air entering.

That said I run my PC with a (temperature controlled) 12cm intake fan at the front, with a 12cm radiator cooling the CPU and GFX sandwiched between 2x 12cm (dial controlled - always at minimum speed) fans mounted inside the case on the back vent. That puts enough air/heat out of the case, my PSU hardly vents anything.

If you want quiet cooling, water cooling is the way to go. It's worthwhile investing in a good quality, quiet power supply too. They can generate quite a bit of noise.