Shall I get more fans when I get GPU?

Soldato
Joined
14 Jul 2005
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Birmingham
Hi all,

When I built my PC, I got the Phanteks P400 case, and the Matterhorn CPU cooler.

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The P400 case came with 2x120mm fans - installed as one intake at the front and one exhaust at the rear. I changed this so both fans were at the front, however the front can take 2x140mm fans instead of 120mm ones.

I am thinking that when I get my GPU (likely an RX480) I may get more fans. My motherboard has 3 system fan headers, 1 cpu fan header and 1 cpu-opt header which I don't know if I can plug a standard fan into that?

I could simply get 1x120mm extra fan for the rear exhaust.

Or I could move one of the front fans to the rear, the other front fan to the CPU cooler as an extra fan on that, and then get 2x140mm fans for the front.

Would my second option be overkill? I think what I would like to achieve is to be able to keep the fans quiet whilst having good airflow. Would more fans, larger fans, spinning slower achieve this?

I have heard GPUs can reach 80+ Celcius, which has prompted the question. I'd rather have more fans spinning quieter than a few fans spinning loudly, if that's the way it works?
 
you can fill every slot with a fan. it depends if its worth it for you. i would if i got a case with only 2 fans. more in than out.
 
Yes, there are a couple of possiblities;
  • Move back fan to front and add 1x more so you have 3x intakes. Even 2x intakes will move more air through the case than 1x intake and 1x exhaust (2x intake fans move almost twice the air of 1x intake and 1x exhaust).
  • Get a 3rd fan of same model (pretty sure they are PH-F120XP) and have 3x front intakes (this give same flow as 2x 140mm intakes).
Good intake fans will flow air right through the case without having exhaust fans same way coolers using 2x fan (even twin towers) are only a couple degrees warmer than running 2x fans. 'Stacking' fans only increase overall airflow because it increases their pressure rating, but their flow rating doesn't change. ;)

With 3x 120mm / 2x 140mm front intakes you should be good. You have a 120mm fan on Matterhorn (great little cooler, they are) and with GPU 3x 120mm should move plenty of air. Plug the case fans to motherboard and set their temp to rpm curves to match CPU and GPU load. You might find this if interest. It's old and I need to edit in more info about fan speed control and how a case only flows the lessor of intake or exhaust fan flow (what goes in must come our / what comes out must go in). https://forums.overclockers.co.uk/showpost.php?p=26159770&postcount=7
 
^ as mentioned, put both fans as intake. The positive pressure created will cause the air to escape from everywhere. This will cause the airflow to be slightly less directional but generally improves temperatures slightly.

2 fans in the original configuration would be fine, but if you want to improve then try the above.
 
I have already moved the back fan to the front - did that straight away when I built pc. I don't think I can have a 3 front fan setup without removing part of the bottom of the case - if you look at the picture above you can see the PSU shroud is in the way of having 3 fans at the front. I could however try and remove the bit that is stopping this, or go for 2x140mm at the front instead?

There seems to be differing opinions on whether a rear exhaust fan is required or not. I don't have one currently as I moved it to the front.
 
1 intake, 1 exhaust. you need to exhaust the warm air.
Cases often do not need both intake and exhaust fans. While a case can only flow as much air in as it flows out, it does not have to be push (intake) / pull (exhaust) to flow properly an more than a cooler or radiator need push / pull. 4 of my 5 systems only have intake fans and they flow so well the temperature difference between room and component intake is 2-3c maximum. The ability of fans to move air against resistance is the key, just as I stated in 5th post.
 
Im getting system temps of 12-14 degrees above room temp (at idle) but this is due to the memory overclock. At 2133mhz i was getting only a couple of degrees above room, but at 3200mhz the cpu and system temps jumped 10 degrees.
 
At a guess I would suspect your cooler intake air temp is 8-10c above room air temp.
System temps are based on cooler intake air temp. Every degree warmer the cooler intake air is is basically a degree warmer the component is. Room air temp is always lower by at least a degree or two. Often cooler intake air temp is 15-25c higher than room air.
 
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