Got a question about airflow.

[LautaroPRZ]

I did so much research about airflow, and based on that i think i built, the best configuration. I have a Corsair 4000D Airflow, that have three fans on the front (intake), one on the back (exhaust) and one on the top right above the CPU (exhaust). Based on my knowledge, that is a positive airflow config, because there are more fans putting in air than taking out. The thing that i can't understand is, when i speed up the intake fans (more cool air inside the case), i can't notice a change in the temps, GPU and CPU. Someone can explain me this? I think that the solution is installing better exhaust fans, the ones that i have just are 1200 RPM max. There is something else thoug, about the ambient temperature, that maybe doesn't matter the speed of the fans, it is the same temperature in the end. I think that i answered myself , but i want to learn more about airflow, i'm instrested in the replies, thank you, have a good day.

 

[Caring1]

Move the rear fan to the top, so there are two exhaust fans that aren't competing for the same air.

 

[dirtyferret]

I did so much research about airflow, and based on that i think i built, the best configuration. I have a Corsair 4000D Airflow, that have three fans on the front (intake), one on the back (exhaust) and one on the top right above the CPU (exhaust). Based on my knowledge, that is a positive airflow config, because there are more fans putting in air than taking out. The thing that i can't understand is, when i speed up the intake fans (more cool air inside the case), i can't notice a change in the temps, GPU and CPU. Someone can explain me this? I think that the solution is installing better exhaust fans, the ones that i have just are 1200 RPM max. There is something else thoug, about the ambient temperature, that maybe doesn't matter the speed of the fans, it is the same temperature in the end. I think that i answered myself , but i want to learn more about airflow, i'm instrested in the replies, thank you, have a good day.

Which CPU do you have?
you have the proper air cooled CPU set up, front in & rear and top rear exhaust. You would need to get higher RPM fans (like much higher) to make even a slight difference in internal temps but you would introduce far more noise. The point of case airflow is move in cooler air and remove hotter air. If you wanted to lower CPU & GPU temps, investing in better coolers would give you better results. Realize some CPUs will run hot regardless of cooler, they will simply push themselves to hot temps.

All that said your temps may be just fine. This is a pretty good video on fan set up although he does confuse heat and hot air.

 

[freeagent]

I like having mine flow front to back.

With spots above the CPU, the front I would have drawing in cool air, and the top rear would be exhaust, or top rear covered, with no fan.

 

[ShrimpBrime]

I did so much research about airflow, and based on that i think i built, the best configuration. I have a Corsair 4000D Airflow, that have three fans on the front (intake), one on the back (exhaust) and one on the top right above the CPU (exhaust). Based on my knowledge, that is a positive airflow config, because there are more fans putting in air than taking out. The thing that i can't understand is, when i speed up the intake fans (more cool air inside the case), i can't notice a change in the temps, GPU and CPU. Someone can explain me this? I think that the solution is installing better exhaust fans, the ones that i have just are 1200 RPM max. There is something else thoug, about the ambient temperature, that maybe doesn't matter the speed of the fans, it is the same temperature in the end. I think that i answered myself , but i want to learn more about airflow, i'm instrested in the replies, thank you, have a good day.

The case flow is to help the coolers (cpu and Gpu) have fresh ambient temps.
The fans on those coolers are responsible for directly cooling the device by blowing directly onto it.

So perhaps the Ambient temps and case flow is optimal, but maybe the device coolers fans could possibly use an upgrade, or perhaps just a more aggressive fan curve to cool the devices. Lowering Ambient temp with optimal case flow and good cpu coolers with more aggressive fan curves may produce better results.

But what are the temps at, and what's the temp goal???

 

[Zach_01]

I did so much research about airflow, and based on that i think i built, the best configuration. I have a Corsair 4000D Airflow, that have three fans on the front (intake), one on the back (exhaust) and one on the top right above the CPU (exhaust). Based on my knowledge, that is a positive airflow config, because there are more fans putting in air than taking out. The thing that i can't understand is, when i speed up the intake fans (more cool air inside the case), i can't notice a change in the temps, GPU and CPU. Someone can explain me this? I think that the solution is installing better exhaust fans, the ones that i have just are 1200 RPM max. There is something else thoug, about the ambient temperature, that maybe doesn't matter the speed of the fans, it is the same temperature in the end. I think that i answered myself , but i want to learn more about airflow, i'm instrested in the replies, thank you, have a good day.

Don’t forget that CPUs and GPUs today are highly dynamic. The moment they sense lower temps eagerly they are trying to work higher or sustain higher clocks.
So whatever temp headroom the higher case airflow creates (which probably isn’t much) it’s probably covered again rapidly by the higher sustained frequency of CPU/GPU assuming nothing else is hitting a limit.

Not easy to draw any solid conclusions about these things. In order to do so you need hard fixed frequencies and especially with GPUs is impossible.

The system may be benefited from better exhaust fans but also may be not. Depends on what hardware you have, how hot they do work, how their coolers work, what fun curve is used, what is the actual ambient temp outside and inside the case, what is the exhaust air temp and so on…

But what are the temps at, and what's the temp goal???

This^^

 

[Degreco]

There is most likely no witchcraft involved, even if you measured correctly and temps stay the same for both scenarios (normal and faster case fan speeds).

First, some questions:
What temps do you get in both scenarios for CPU and GPU? Do you use an AIO or an air cooling solution for your CPU? You do not apply a water cooling solution for the GPU, I assume!? Also, do you use a GPU or CPU centric workload to measure temps (or both)? What apps/games do you use to measure temp. And how do you measure.

Here is the reason for all those questions:

1. There is a limit for your lower temp treshold as your heatsinks works on a temperature differential. The ambient temperature has much more impact than your fan speed unless your case fans are on very low or zero rpm modes. So, if your case temp is basically comparable to your ambient temps you can increase the fan speed how much you want, you are as low as you can get it and temps will stay where they are.

2. Use sustained workloads, to get a better picture, because some workloads are too short, stuff needs to actually warm up and fan curves are at place. Also keep in mind, software measurement by sensors is not the best way to accurately measure heat in the case. Use a point and shoot thermometer gun, they provide better and more accurate temperature readings.

3. GPU temps: The lower and possibly middle front fan intakes push air to the GPU. But your GPU Fans operate independently, so even if there is more air available due to the faster fan speed, but not more cooler air per se, the GPU temps will stay very much the same in GPU load situations. Also most modern GPUs have a semi-passive cooling enabled, so even if the GPU load is increasing more air will have no measurable effect if a certain treshhold in the GPU fan curve is not passed. Hence my question if you test GPU or CPU centric. Also, is the GPU load at 100% or not? If not, you are basically not testing for GPU temps and faster case fan speeds will get you nowhere, because the GPU is not a full load.

4. CPU temps: You did not mention your CPU cooling type. If you use, let's say an 360 AIO, any additional volumes of air around the CPU will do almost nothing to the plain CPU temps, because the AIO will take care of most of that. More air will of course lower tems for VRM and possibly m.2 temps, but the CPU load temps will stay comparable for both case fan scenarios.
If you cool your CPU by air more air should obviously have some effect. BUT even then temps can stay the same if you just shovel more of the same ambient air into the case! If more air is available, your CPU fans don't need to work that hard. This is especially the case if you just push more air of the same ambient temperature into the case, but not cooler air. Also, is the CPU load at 100% in your tests?

5. Fan curves and normalized tests: You need to measure against normalized fan speeds for the CPU and GPU to actually understand the impact of the increased fan speeds. Deactivate fan curves, use fixed speeds on CPU and GPU fans and measure for both scenarios again - with sustained workloads on CPU and GPU, of course.

Hope, this helps a bit.

 

[Shakallia]

Hello,

From my own experience, the best set up is 3 intakes front, 2 intakes in the bottom if possible (don't know much about your case), and one single exhaust in the back, putting exhaust in the top never made a difference to me, but if you really want to put one, well just put only one in the back.

 

[Kapone33]

Best (In my opinion) is to have high RPM fans in the front. Your AIO exhausting from the side and the GPU rad (If you have one on top) as my CPU is an X3D it is much easier to cool than the 300 watts my 7900XT will pull in some Games. You know that rear exhaust is working when you feel the hot air blowing out the back. If no GPU rad then the CPU rad at the top makes sense.

 

[eidairaman1]

Best (In my opinion) is to have high RPM fans in the front. Your AIO exhausting from the side and the GPU rad (If you have one on top) as my CPU is an X3D it is much easier to cool than the 300 watts my 7900XT will pull in some Games. You know that rear exhaust is working when you feel the hot air blowing out the back. If no GPU rad then the CPU rad at the top makes sense.

My case has a 230 up front and a 230 at top, 140 on bottom and 140 out back.

 

[Ruru]

Move the rear fan to the top, so there are two exhaust fans that aren't competing for the same air.

I have the same case as OP and I have a rear fan and two top fans as exhaust.

 

[lepudruk]

I did a lot (like: A LOT) testing with various cases and AIO/fan orientation and finaly came to the solution that suites me best:

My previous build was using Lian Li Lancool III with AIO mounted in front (as an intake), with 3x 140mm fans on top (exhaust) and 1x 140mm rear (exhaust too). That was a good build and the temps were fine (not perfect though: GPU's temps were superb, CPU's were just ok) - the problem was that in such configuration the rig was quite loud.
With present configuration I managed to lower the temps all around (despite OC on CPU) and achieve almost grave silence

 

[Shakallia]

I did a lot (like: A LOT) testing with various cases and AIO/fan orientation and finaly came to the solution that suites me best:

View attachment 373778
My previous build was using Lian Li Lancool III with AIO mounted in front (as an intake), with 3x 140mm fans on top (exhaust) and 1x 140mm rear (exhaust too). That was a good build and the temps were fine (not perfect though: GPU's temps were superb, CPU's were just ok) - the problem was that in such configuration the rig was quite loud.
With present configuration I managed to lower the temps all around (despite OC on CPU) and achieve almost grave silence

I think the 3 exhaust at the top are counter productive, they're probaly sucking some of that fresh air out too.