[SOLVED] GPU raising AIO/CPU temps?

Apr 19, 2021
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Specs:
10600k w/EK240MM AIO
Rosewill PRISM S ATX case
RTX 3070 EVGA XC3


So I'll get right to it: I have my AIO mounted to the side of my case with the logo side of the fans facing towards the glass side panel. In addition to the two fans on the radiator, I also have one exhaust fan near the PSU and one other intake fan at the bottom of my case. The issue I am having is that whenever I hit both my GPU and my CPU with a 100% workload, the CPU temps will go up by about 3-4 C while the gpu goes up by about 1C. From my reading, I know a lot of people have an issue where the air from their radiator heats up the GPU, but I have yet to find any thread where someone had the air from their GPU heating up their radiator. How can I solve this? (is this even solvable or should I just reinstall my old air cooler?)
 

Karadjgne

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So that's you. Basically.

Rosewill had a neat idea giving versatility to that 2x hdd/ssd area by tossing in 240mm AIO compatibility. Except for one thing. As far as I can see it's pretty solid behind that rad. Even removing the hdd tray doesn't do all that much for exhaust, so what you actually get out of that is a ton of backpressure which is going to fight your fans.

Honestly, I'd flip them 180°, make the aio as an intake, not exhaust. A Vacuum behind that will be a lot stronger source of air than an exhaust because vacuum is not reliant on direction.

What's to consider is you are right about the gpu heating up the cpu, but totally wrong about how. You have 1 intake source, below. You have 2x exhausts in that top corner (rear fan and psu), and you have fans on the gpu pulling hard under loads. The air from that intake source wants to go Left. Simply put you are starving the aio, which is already under duress from backpressure when both are under 100% loads.

You aren't heating the aio/cpu, you are starving it of cooling ability, and fighting the gpu source of air. When the gpu is basically idle and cpu under load, the air goes Right. Turn up the gpu fans, adding load to the psu which kicks up fan speeds, it reverses. Flip the aio fans around, make it intake by pull and now you have airflow from right side to left side of the picture. You create a solid airflow path instead of a divided one.
 
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Karadjgne

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Installing your old cooler will only exacerbate the issue, your cpu temps will be considerably warmer.

You have 1 intake fan at the bottom and 1 exhaust fan. You have a side mounted 240mm rad that's pulling in gpu exhaust straight up from the glass.

The airflow characteristics in that case are not good at all, it's a wonder you see such little change with a full workload.

Dumping that many watts into a case is going to raise ambient deltas and that's going to raise the baseline coolant temp, making it less efficient.

You need better airflow, not worse aircooling. And sweating over 1-3°C under hypothetical 100% cpu/gpu combined loads isn't doing you any good. Nobody runs that kind of pc abuse as it kills performance.
 

rubix_1011

Contributing Writer
Moderator
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Cooler Troubleshooting and Questions


High CPU and GPU temperatures:

This could be caused by a few different things, please don't automatically assume 'the cooler is not working' without also checking if the case airflow is sufficient.

Remove the side panel of the PC case. Orient a house fan (desk or box style fan) to blow air into the case, directly over components at the highest setting.

This will represent a case with the best possible airflow possible. For reference, the fans I am providing as examples would look like the items below (just to clarify for anyone who might want reference)



Re-test as you have normally done - play games, run benchmarks, etc. to get to where temperatures were normally seen to be higher than they should. Normal room temperature is usually between 20-24C or 68-75F. Please note that every air or liquid cooler operates as a product of delta-T over ambient, meaning that if the PC is operational (simply turned on), it is impossible for the CPU to display a temperature below ambient room temperatures. If it is, this is likely a bug in software temperature reporting either from the desktop UI or the BIOS reading it incorrectly.

With the fan running at full speed, if temperatures drop by 5-7C or more, case airflow is one major issue to contend with. You will need additional fans or better fans for your setup in order to optimize air in and out of the chassis. This might even require consideration for a new PC case or leaving the side panel partially open during sessions of heavier computing until these items are corrected.

If your temperatures remain relatively the same (difference less than 1-2C), then you likely have an issue with the cooler in question (if CPU is hot, CPU cooler, if GPU is hot, GPU cooler). It would be good to then approach the next steps by thoroughly cleaning the cooler with compressed or canned air and ensuring there are not large blockages in cooling fins or on fans, etc. This might require the cooling fans to be removed from the heatsink or radiator to ensure there is not a buildup of pet hair, dust or even carpet fibers which can trap additional debris. Please ensure the PC is turned off and unplugged during this process to prevent unwanted startup to keep fingers safe from fan blades or accidental shorting if you happen to drop a screw onto other components during fan removal.

Removal of the cooler and re-application of thermal paste & re-seating the cooler can also be beneficial once cleaning of the cooler is ruled out by retesting the steps above.
 
Apr 19, 2021
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First off, thanks for the very helpful posts:

So I have replaced the thermal paste on the cooler already because that’s the first thing that came to mind when I saw the temps I was getting (the AIO came with pre-applied paste) in hindsight that was probably not needed but replacing the paste doesn’t seem to have made anything worse at least.

Secondly, on the issue of airflow, yes I suppose with the way the case is right now, the AIO is probably pulling in a bunch of hot air from the GPU. And yes, with the side panel off (even without putting a fan next to it which is a good idea and I’ll try that soon) I do get a drop of at least 5C on cpu temps and around 3C on GPU temps.

So I’m going to ask y’all to tell me what the best option is:

Should I buy a set of three case fans and replace the one fan at the bottom for intake?

or

I actually have an old ibp prebuilt with a case that will fit my board (atx). It has been running as a headless server for about a year. The case already has three intake fans at the front and I have confirmed it has space for a 240mm AIO rad to be mounted at the top where there is currently nothing mounted. Should I run a case swap?

or

something else?
 

Karadjgne

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Case swap wouldn't be a bad idea in that respect.

But, it's all dependent on the actual temps. If you are hitting decent temps and only seeing that 1-3°C rise when maxing out both cpu and gpu, I'd not bother, you aren't going to be doing that on a continual basis at least.

When is good enough simply that? For most cpu/gpu anything over @ 70/80 is pushing it, with anything less not making a difference. 65° or 55° being the same thing to the cpu or gpu.
 
Apr 19, 2021
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Case swap wouldn't be a bad idea in that respect.

But, it's all dependent on the actual temps. If you are hitting decent temps and only seeing that 1-3°C rise when maxing out both cpu and gpu, I'd not bother, you aren't going to be doing that on a continual basis at least.

When is good enough simply that? For most cpu/gpu anything over @ 70/80 is pushing it, with anything less not making a difference. 65° or 55° being the same thing to the cpu or gpu.
Just noticed I never listed my actual temps:

please note my cpu is running at 4.8 with avx offset of 2 and my GPU is at 113% power limit and +120 core.

So first I’ll list the temps I get in unrealistic loads (side panel is on):

MSI Kombustor + AIDA64 FPU only (4.6ghz CPU~82 Max GPU ~71-72 Max
MSI Kombustor + Cinebench r23 30min loop: GPU temps=71C Max CPU=80 Max

Now for realistic:

Control (rtx on DLSS on 1440p output res) 30 minutes: CPU: 71-73 GPU=~68C

Destiny 2 1440p max settings 30 minutes: CPU 71-73 GPU=~66-68
I could list other gaming workloads but the story is much the same, GPU temps just below 70 cpu temps below 76 always. Now I recognize this is fine but I’m having to run the cpu at 4.6 AVX and 4.8 non-AVX. I’m unable to OC even slightly on the cpu because going to 4.7 AVX (lowering the offset) pushes the temps into the low-mid 80s for realistic workloads and for the 100% max utilization load it pushes cpu temps into the borderline 89-91C. As for the GPU it manages to stay above 2000mhz core at all times in games.

I think I will probably do a case swap on the weekend, but before I do that, do you think adding two more intake fans at the bottom of the existing case will solve the issue or would it just be a waste?
 
Last edited:

Karadjgne

Titan
Ambassador

So that's you. Basically.

Rosewill had a neat idea giving versatility to that 2x hdd/ssd area by tossing in 240mm AIO compatibility. Except for one thing. As far as I can see it's pretty solid behind that rad. Even removing the hdd tray doesn't do all that much for exhaust, so what you actually get out of that is a ton of backpressure which is going to fight your fans.

Honestly, I'd flip them 180°, make the aio as an intake, not exhaust. A Vacuum behind that will be a lot stronger source of air than an exhaust because vacuum is not reliant on direction.

What's to consider is you are right about the gpu heating up the cpu, but totally wrong about how. You have 1 intake source, below. You have 2x exhausts in that top corner (rear fan and psu), and you have fans on the gpu pulling hard under loads. The air from that intake source wants to go Left. Simply put you are starving the aio, which is already under duress from backpressure when both are under 100% loads.

You aren't heating the aio/cpu, you are starving it of cooling ability, and fighting the gpu source of air. When the gpu is basically idle and cpu under load, the air goes Right. Turn up the gpu fans, adding load to the psu which kicks up fan speeds, it reverses. Flip the aio fans around, make it intake by pull and now you have airflow from right side to left side of the picture. You create a solid airflow path instead of a divided one.
 
Reactions: themanwithaplan
Apr 19, 2021
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So you’re totally right, that case pictured in your post is what mine looks like except I have one intake fan instead of three. And the second thing I should mention is that I have the radiator mounted tubes down since that was EK’s “recommended” config in their manual, would that also possibly be having a negative impact on temps?

Second, when you say I should make the aio an intake by pull, basically I should just take the fans and flip them around so that they pull air through the radiator and the back panel? As in the front of the fans should just face inwards towards the radiator right?
 
Apr 19, 2021
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Update: Huge thanks, I flipped the fans as you suggested and retested both cpu and GPU temps by running Kombustor and AIDA FPU only together for one hour and the core temps never went past 77C, mostly they hovered around 69-72 for the last 30 minutes of the test. , GPU never went past 70C either.

Now just one last question… if I were to put two more fans at the bottom (only place there’s room) in addition to the one I already have, would I see even a slight further improvement in cpu or gpu temps or would it be pointless? And should I place these fans as exhaust or as intake?
 

Karadjgne

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3 fans across the bottom is fine, best as intakes. They will strictly be for feeding the gpu, since the aio fans are feeding the cpu. So that particular set of fans don't need to be run at uber high rpm, there's 3 of them.
 

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