Question GPU temp drops 20 degrees with undervolting, but now the CPU overheats ?

[INULLO]

Hi Guys,
I got and used RTX 3090 for 3d rendering. Saw so many videos about the Vram overheating issue.
Tried simple undervolting 1650mhz 798 and temps dropped from 105 to 82 degrees performance drop not more than 1-2% percent.
Now all is fine one thing I don't understand is why the cpu gets so hot while it is rendering.( GPU rendering only CPU is 20% workload max but reaches 94 degrees on occasions.
If I render only with CPU 100% load it hardly gets over 85 degrees.

I assume that is the heat coming from the GPU but why is the system not tracking that heat and compensating with the fan when such temps are reached on the CPU ?
ryzen 3900x , has a nice big cooler on top.
and my last question will be though GPU is perfectly normal and stable on the gpu-z it shows PErfcap Reason as idle..is that how it should be because of the undervaulting?


Thanks
Kind Regards,

 

[Lutfij]

When posting a thread of troubleshooting nature, it's customary to include your full system's specs. Please list the specs to your build like so:
CPU:
CPU cooler:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:
Monitor:
include the age of the PSU apart from it's make and model. BIOS version for your motherboard at this moment of time.

for 3d rendering
Name of the app that you're using to tax the GPU? You also need to mention what you had prior to the RTX3090. Dud you run DDU prior to dropping in the RTX3090?

 

[INULLO]

Hi,

Sorry here ate the specs:
ryzen 3900x
Cpu Cooler: Cooler Master Hyper 212 EVO
b450m ds3h
ram: 64gb Corsair Vengance LPX
ssd:

Western Digital SN530 512 GB NVMe SSD​

3090 rtx MSI Ventus
Fractal Design r4
Eizo

3d app tests vray....before that I had 980Ti MSI 6gb

DDU not sure what that means.?

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