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- 8 Sep 2010
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Over the past few weeks, since upgrading to a 5090, I noticed my CPU running quite warm under medium load. I initially put it down to the warmer weather.
It's cooled by a Noctua single fan tower and the case is a 4000D airflow with the stock 1 in, 1 out fan configuration.
I decided to replace the fans with Noctua units and add an additional 150mm to the front. I repurposed stock fans to exhaust at the top of the case with an additional Noctua fan at the rear for exhaust.
Running a few benchmarks, I noticed that it didn't really solve the problem. I tweaked all the fans to consistent 45% with a critical temp set to 85. Again, the cpu just kept climbing when the GPU was fully loaded.
It then dawned on me that the GPU is exhausting directly into the path the cpu draws from (fan facing the front of the case) and was gradually getting heat soaked while the GPU was under full load.
After tweaking fan speeds a bit more, and slightly undervolting the CPU (-20mv), I stumbled upon advice to undervolt the 5090 to reduce it's temp under load.
I followed a basic guide which, if I recall correctly, flatlined at 900mv, 2500mhz.
After some more testing this has basically solved the issue with a couple of percent performance loss on the GPU.
I suspect the true fix would be to water-cool the CPU to remove the GPU exhaust issue from the equation.
Has anyone had a similar issue with a 5090 or similar and a tower fan on the CPU? Would water-cooling be the optimal approach here?
It's cooled by a Noctua single fan tower and the case is a 4000D airflow with the stock 1 in, 1 out fan configuration.
I decided to replace the fans with Noctua units and add an additional 150mm to the front. I repurposed stock fans to exhaust at the top of the case with an additional Noctua fan at the rear for exhaust.
Running a few benchmarks, I noticed that it didn't really solve the problem. I tweaked all the fans to consistent 45% with a critical temp set to 85. Again, the cpu just kept climbing when the GPU was fully loaded.
It then dawned on me that the GPU is exhausting directly into the path the cpu draws from (fan facing the front of the case) and was gradually getting heat soaked while the GPU was under full load.
After tweaking fan speeds a bit more, and slightly undervolting the CPU (-20mv), I stumbled upon advice to undervolt the 5090 to reduce it's temp under load.
I followed a basic guide which, if I recall correctly, flatlined at 900mv, 2500mhz.
After some more testing this has basically solved the issue with a couple of percent performance loss on the GPU.
I suspect the true fix would be to water-cool the CPU to remove the GPU exhaust issue from the equation.
Has anyone had a similar issue with a 5090 or similar and a tower fan on the CPU? Would water-cooling be the optimal approach here?
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