Question about AMD Ryzen 9 7900X

I also got one, also with a 4090. Everything runs smoothly for me. I have no problems or any jerkiness. The only thing that doesn't work for me is the bluetooth, but the CPU has nothing to do with that.

I have the processor. If the system is to be built with a 4090, I would not currently recommend it. Many problems with the BIOS.
You can find enough performance tests on the internet.