Heatsink fan direction

Will82 · 15 Jan 2015 at 19:04

I just installed a Cooler Master Hyper TX3 Evo I had lying around, on a non-overclocked i5 3570K, because I couldn't handle the noise of the stock cooler having recently installed a GTX 970.

I know it's not a great cooler and I plan to upgrade it, but I was wondering about the placement of the fan. My setup is one intake fan, then above the 970 I have the CPU fan to the left of the heatsink, sucking air from it and an exhaust fan just behind it, sucking the air out of the case.

Idle temps for the GPU and CPU are between 27-35, which is fine, however I loaded up AC Unity in windowed mode, as it's the most CPU intensive game I have, and after only around five minutes the temps across all cores had reached 73c, which seemed a little high to me.

My question is, would I perhaps see a difference if I positioned the CPU fan to the right, so it blows air onto the heatsink and towards the exhaust fan? Also, it'd be great if someone could recommend me a replacement cooler. My budget would be around £50 and I'd like a decent balance between quietness and cooling capabilities. Thanks in advance.

RJC · 15 Jan 2015 at 19:07

Ideally you need the fan drawing air from the front and pushing ot through the heatsink then allowing the extract to remove the warm air.

New cooler:

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1 x Alpenföhn Matterhorn Pure Edition CPU Cooler £29.99
Total : £35.96 (includes shipping : £4.98).

But check your case dimensions

Will82 · 15 Jan 2015 at 19:29

Thanks for the quick reply. So it probably would make a difference to position the CPU fan so it's pushing air through the heatsink? I'm gonna try it now as it doesn't involve much effort.

I was looking at Alpenföhn coolers and that one will easily fit my case (219mm width). Thanks again.

Will82 · 15 Jan 2015 at 21:35

I changed the fan orientation so it's pushing air through the heatsink, towards the exhaust fan and it does seem to have dropped temps a few degrees. I can't help noticing though that they're wildly fluctuating at around a 3-10% load, anything from 25c to 46c across the four cores. Is that normal? Screenshot below.

Audigex · 15 Jan 2015 at 23:03

The temperature being between 20-45 degrees at idle isn't a major issue, especially if your CPU fan is running off your motherboard - it probably only bothers ramping the fan speed up at 40-50 degrees (below that temperature it figures you'd prefer the lower noise)

The difference across the cores may indicate a slight mounting issue - 26 vs 29 isn't too worrying, but 32 compared to 46 presumably at a similar time may suggest the heatsink isn't mounted properly. You need to run a load test to be sure.

Ramp your load level up with a stress test, keep an eye on the temperatures for half an hour and see what you get. If the max is within 5 degrees you're fine, within 10 is probably ok as long as you've got a decent amount of headroom to your TJMax, and much more than 10 I'd consider remounting even if you have headroom.

Will82 · 17 Jan 2015 at 13:11

Cheers for the advice. I had a few issues installing it and had to remove the motherboard so I think I'm gonna just invest in a better cooler instead of remounting this one. The system seems to be stable right now, even after a long gaming session. It shot up to 46c when, for some reason, the load went up to around 26% very briefly.

I had an issue with Firefox using way more CPU than usual which I've sorted now, so perhaps that explains the usage spike. I can access the back of the motherboard but this cooler has clips like the Intel stock one, making it a nightmare to fit without removing the motherboard. A decent upgrade with a back plate fitting should be a lot easier to install.