200mm vs 120mm on Radiator configuration

Darziak · 24 Jun 2021 at 00:55

I've got a 3090 card which has a radiator and 2 120mm fans connected to it. I've also got a aio for the cpu which also has 2 120mm fans, but my case has 2 200mm fans.

My question is should I keep the 120mm fans attached to the radiator and remove the 200mm fans or do the opposite?

I know I can't use both because of the that would mess with the fan speed and such.

The Top of the case gets taken by one and the only space left is the front.
New GPU not installed yet as shown in this picture.

Pocket10s · 24 Jun 2021 at 08:18

Really interesting question; why not test it??

LuckyBenski · 24 Jun 2021 at 10:28

Pocket10s said:
Really interesting question; why not test it??

This is the biggest and best question with all things airflow and temperature related! Try everything. My quietest PC had two intakes on the roof and one exhaust fan, with a passive CPU cooler. Totally unorthodox airflow.

I can't see what the mounting is like but could you keep the top 200mm and mount the graphics cooler in the bottom position?

Darziak · 24 Jun 2021 at 14:17

Pocket10s said:
Really interesting question; why not test it??

I wanted to see peoples opinions before doing it.

LuckyBenski said:
I can't see what the mounting is like but could you keep the top 200mm and mount the graphics cooler in the bottom position?

The front is 200mm, I could mount the GPU radiator to the bottom but airflow would be bad and with the heat that it generates it would probably kill off my PSU on long gaming sessions.

I'll have a go with mounting the CPU radiator to the front keeping the two 200mm fans. it kept to 30c with the two 120mm fans.

Interesting, 200mm provides 24c on idle instead of 30c from 120mm. I thought it would be more hotter because the fans aren't purely concentrating through the radiator.

hlennie · 28 Jun 2021 at 06:49

How about keep the 200's in place and have the 120,s in pull config on rad mounted behind your 200's

Darziak · 1 Jul 2021 at 01:20

hlennie said:
How about keep the 200's in place and have the 120,s in pull config on rad mounted behind your 200's

I've seen multiple tech channels say that's not a good idea because of the different fans giving different airflow speeds.

hlennie · 1 Jul 2021 at 01:25

Just try it see what happens it might work out great. Try with 200s on and off

MikeTimbers · 8 Jul 2021 at 20:00

PSU fan should be pointing downwards pulling air from underneath through the PSU. Case temps should have no effect on the PSU then.

Is the radiator with the 3090 a 240 (2x120) or a 120 with two fans in push/pull? If the latter put the radiator on the rear exhaust. If the former, put the 240mm at the front. If you must keep the 200mm fans you could buy or build a shroud that connects to the back of the 200mm fan and funnels down to a 120mm size. The pic below shows a shroud from a Vauxhall heatercore down to a 120mm fan (back in the days when this was state of the art!) made from some aluminium sheet and some calculated cutting with tin snips.

Darziak · 8 Jul 2021 at 21:33

I've mounted the CPU radiator (240mm) to the front, using the two 200mm fans which gives a idle 25°c from the pump.
The GPU Radiator (240mm) I mounted to the top with an idle of 28°c. The two 120mm fans attached to the GPU radiator have the wires going into the GPU itself so I'm unable to remove them without having to take apart the GPU.
PSU is facing down.

Fans are set to pull in from front and out from back and top.

Setup looks to be working fine, staying below 70°c when running a game.