Question Faulty Power Supply ?

mafi

Distinguished
Oct 15, 2008
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18,535
I have a really weird problem.
My PSU is a 2017 750W Corsair RM750W Gold certified.
In the autumn of 2022 when I had the same PSU, an i7 4790K, 16GB RAM and a GTX 1660Ti, my PC started to randomly restart or even shut. At first it happened once every 2-3 days, later several times a times a day until my PC simply failed to post.
I removed the CMOS battery and disconnected HDD, SSD, the GPU.
I was able to boot only with one kit of Ram, and the integrated graphics card. Then I installed the second memory Kit, the SSD, the HDD, and the GPU.
How did I solve the problem ? I disconnected all the case fans. Even before I was running my PC with the case opened.
Then everything went fine.

This summer I upgraded to AMD Ryzen 7700, 32GB DDR5 6000 and RTX 4070, replaced the old case with a new one, but kept the old PSU.
A day after installing the new case and connecting the case fans my PC started crashing again. The next day it simply failed to post.
I took the same steps like two years ago and disconnected all case fans and run my PC with the case opened. Now everything works fine.
I undervolted the CPU and limited the max turbo boost frequency to 5 Ghz instead of 5.3 Ghz and now it doesn't exceed 70 degrees Celsius even in stress tests and it's 100% stable.
I remember MSI Afterburner showing around130W power consumption for the 1660Ti in stress test when the GPU was at 100% usage.
Now it shows around 200W for the RTX 4070 at 100% load. I can run stress test or play intensive games without any problem as long as there's no case fan running.

And I have another problem with Windows 11. Sometimes the spinning wheel gets stuck and windows won't boot. Another time windows boots, I can move the mouse pointer but windows is very unresponsive and I have to restart or shut down.