I have just replaced my 5800x with a 5950x and faces high temp issues. Note that I am running on air cooling (Noctua NH D115S) , waiting for my watercooling to arrive.
The MB is an Asus Crosshair VIII Dark Hero.
I am running Cinebench at 76°C and games at permanent 91°C!!!
Tried replacing thermal paste, no difference!
In addition to that, benchmark results look a little bit on a low side at stock (multi core 24894/single core 1589).