Best general fan speeds for optimal cooling in a 3x140mm front/360 aio top.

MachP · March 12, 2022

If I have a 3x140mm front/360mm aio top fan in my p400a system what is the best way to make sure air flows throw properly over componants like my ram. Like should the top 360 mm aio fans run at a rate of only ~75% of the rpm of my front 3 fans?

Pandur · March 12, 2022

You want the front fans to move a bit more air than the top fans. If you have 6x identical fans, I would say maybe a 10% delta. If they are different you can't just compare rpm anymore. Different fans perform different even at equal rpm.

No need to overthink this, unless you have overheating issues today.

Demonic Donut · March 12, 2022

You don't need to worry about it. If your gpu is ok, your VRM and RAM etc will be fine as well. They don't need direct airflow, as long as there is circulation in the case you'll be fine. With your fan setup there is plenty of turbulent airflow.

Set your fans to the speeds that give your CPU/GPU good temps and you are happy with the noise level.

MachP · March 16, 2022

On 3/12/2022 at 11:46 AM, Demonic Donut said:

You don't need to worry about it. If your gpu is ok, your VRM and RAM etc will be fine as well. They don't need direct airflow, as long as there is circulation in the case you'll be fine. With your fan setup there is plenty of turbulent airflow.

Set your fans to the speeds that give your CPU/GPU good temps and you are happy with the noise level.

True but I'm running my ram at 3800cl14 and unless I put a ran on my ram (on top of my massive GPU) under a ram stress test the temps hit unstable ranges. Otherwise my case's airflow is extremely over the top good. I still need to alter the ram voltages to their most minimum so I don't put out as much heat.

Demonic Donut · March 16, 2022

1 hour ago, MachP said:

True but I'm running my ram at 3800cl14 and unless I put a ran on my ram (on top of my massive GPU) under a ram stress test the temps hit unstable ranges. Otherwise my case's airflow is extremely over the top good. I still need to alter the ram voltages to their most minimum so I don't put out as much heat.

What is your ram voltage at?

As I said, go with the max speed level you are comfortable with for sound honestly. Fluid dynamics is complicated.

You can try modifying fan speeds while stressing the system to see what temperatures do. I would assuming if all fans are at 100pct, you would be slightly positive for pressure. As the 3 140mm will move more air than the 3 120mm, assuming restriction from front mesh and the radiator are roughly the same. Can you feel air being exhausted through the rear port or at the empty pcie slots?

You can always add a fan to directly blow on the ram modules if you really need it.

MachP · March 16, 2022

3 hours ago, Demonic Donut said:

What is your ram voltage at?

As I said, go with the max speed level you are comfortable with for sound honestly. Fluid dynamics is complicated.

You can try modifying fan speeds while stressing the system to see what temperatures do. I would assuming if all fans are at 100pct, you would be slightly positive for pressure. As the 3 140mm will move more air than the 3 120mm, assuming restriction from front mesh and the radiator are roughly the same. Can you feel air being exhausted through the rear port or at the empty pcie slots?

You can always add a fan to directly blow on the ram modules if you really need it.

I am OCing at 1.53v on the DRAM. I do have a fan blowing on it during Ram stress tests with a GPU load on so the ram fan is working. I forgot to mention I have a 140mm fan in my exhaust so i think that helps as well.