Increasing fan speed does not reduce temp

[Trev_pHi]

Hi all,

I'm running a i7 2600k OC @ 4.4ghz ~1.285 vcore under load on a P8P67 evo. My cooler is a bequiet darkrock pro 3 and the temperatures are fine however I've noticed that when I change the fan speed from 800rpm to 1600rpm the CPU core temp remains the same (tested both settings under load and idle) Does this just mean the fan, even at 50%, is blowing away the heat faster than the heatsink can extract it from the CPU? Or could it be bad airflow in the case resulting in high ambient temps?

I have a HAF-X with 1 x 230mm intake (front) || 1 x 200mm intake (side panel) || 1 x 120mm GPU fan || 1 x 140mm exhaust fan (rear) || 2 x 200mm exhait fan (top). All are quiet, low rpm fans but I'm pretty sure the airflow is quite good...

The case is in teh corner of my desk with sound proofing foam only an inch from it and I notice the air around the case is quite warm so maybe the exhaust is just getting sucked back in? I tried moving it out from under my desk for a few minutes and the temps didn't really change. I even got a pedestal fan to try and clear the hot air but no change.

My temps are fine, I'm just curious as to why doubling the fan speed has no effect.

 

[Karsten75]

My first guess is that your air flow is inadequate with the soundproofing/insulation around it.

What I find puzzling is that you ask for help with temperatures, seems quite informed on the subject and then fail to mention either any specific temperatures. Neither ambient, load or no-load temps are mentioned at all. Why is that?

 

[VincentP]

The heat sink will only dissipate so much heat from the CPU.
There is a minimum temperature above ambient that you will never get below by blowing more of the same temperature air over the heat sink.

 

[Trev_pHi]

My first guess is that your air flow is inadequate with the soundproofing/insulation around it.

What I find puzzling is that you ask for help with temperatures, seems quite informed on the subject and then fail to mention either any specific temperatures. Neither ambient, load or no-load temps are mentioned at all. Why is that?

Because it's irrelevant. Temps are normal, I'm only looking for a reduction of a few degrees when I increase the fan rpm. Whether it;s 70 degrees or 50 degree isn't relevant unless im living in an extreme environment.

But:
idle is around 34 degrees both with 800rpm and 1600rpm
prime95 is around 70 degrees after 5+ minutes both with 800rpm and 1600rpm

The sound proofing isn't attached to the case, it's attached to the desk which leaves about a 1 inch gap between the case. It sort of insulates the air though which may be increasing the ambient temp in the immediate vicinity of the PC however removing the PC from under the desk makes no difference.

 

[Karsten75]

My first guess is that your air flow is inadequate with the soundproofing/insulation around it.

What I find puzzling is that you ask for help with temperatures, seems quite informed on the subject and then fail to mention either any specific temperatures. Neither ambient, load or no-load temps are mentioned at all. Why is that?

Because it's irrelevant. Temps are normal, I'm only looking for a reduction of a few degrees when I increase the fan rpm. Whether it;s 70 degrees or 50 degree isn't relevant unless im living in an extreme environment.

But:
idle is around 34 degrees both with 800rpm and 1600rpm
prime95 is around 70 degrees after 5+ minutes both with 800rpm and 1600rpm

The sound proofing isn't attached to the case, it's attached to the desk which leaves about a 1 inch gap between the case. It sort of insulates the air though which may be increasing the ambient temp in the immediate vicinity of the PC however removing the PC from under the desk makes no difference.

I assume you're one of those people that when you go to the doctor for a headache, you'll tell them that they cannot test your eyes, since your eyesight is irrelevant to you getting headaches? If you ask us a question, it's us that decides what's relevant.

Since you didn't mention ambient temperature, I'll assume it's around 28C. regardless of how much air you blow over a heatsink, you cannot cool it to less than around 5C of ambient. That would explain the 34C.

I fully understood that your insulation is an inch around the outside of your case, but it merely increases the dimensions of the enclosed air.

As for why the under-load temps don't change. It may be that that's the thermal efficiency of your cooling solution - the rate at which heat generated by the CPU under load is transferred to the heatsink. if that is the case, then no amount of air over the heatsink can remove the heat that has not yet reached the heatsink.