Hi,

I currently have an Arctic Freezer Pro 7 (installed the wrong way round, drawing air in from the back of the case, but that's first-time builds for you) on my CPU, which is a cheep 'n' cheerful E5300 at 3.83GHz: overclocking is not too tough with a 13* multiplier

Running at idle, the Core Temp app tells me the processor is about 28-30C, which goes up to around 42C during normal load (Assassin's Creed ) and I have never seen it go over 47C when given hefty excercise.

However, the fan on the CPU cooler is the loudest thing in the case - worse than the stock cooler on the HD4650 GPU, which I am going to replace with a passive cooler, the Accelero S2.

My question is, what to do about it? I don't want to spend £50, that's as much as the chip was! Can I attach a silent fan to the existing heatsink? Or is there a quieter cooler for less than around £25? I like the cool running temperatures as they are, will turning the fan speed down make a huge difference?

You can either replace the fan (I do this on media centre builds) or try turning it the correct way round to see if it drops the temps & the noise.

If I turn the cooler around, will I need to re-apply thermal paste to the interface? I'm kind of paranoid that if I shift the thing it will stop working so well.

Yes you'll need to clean off the old stuff & put a new layer on.
You'll need to do that with a new cooler as well.

OK thanks for that.

Also, will I ned to buy a specific type of fan for the cooler, as it plugs into the motherboard for speed control, or will any 3-pin molex fan be suitable?

Any 3 pin will do.

Noctua fans are lovely and quiet and shift air.

Agreed, Noctua and Scythe are generally the best for CPU cooling.

Sharkoon are good for case cooling, but don't have the throughput for CPU cooling without getting too loud.

Sounds like something's up to me. My Freezer 7 is extremely quiet. Even the stock cooler on my 66GT is louder and that graphics card is very, very old. Also, my PSU is probably louder. The Freezer 7 Pro was THE thing to have for ages and low noise was one of the reasons.

I have ordered a quiet fan to go on the front of the heatsink, hopefully that should sort things.

Thanks for your suggestions!

Thermalright Ultra Extreme 120 or whatever it is can be run passively (no fan) so long as you've got decent enough throughflow on your case.

I've always found the AC7 to be WAY too loud =/

The SilenX iExtrema case fans shift a lot of air and are very quiet.

OK, the quiet fan is on the existing AC7 heatsink and the passive cooler is on the GPU - silence at last!

Now I have to get on with cable tidying...