I did find that increasing the LLC to 4 and using about 1.3 vCore i was able to hold CB23 at the 4675 mark on all cores longer than an instant crash but temps don't seem to be it. Yep, right around the 80-83c mark it reboots or stops responding in CB23 with a fixed vCore of anything. However, no matter what I try, I can't get a table manual OC and had to settle for PBO +100, which is only ~100 points lower score in some benchmarks. This allowed me to go to 3933 RAM and 1966 FCLK 1:1. I switched to the Asus because the BIOS had the proper SMU of 56.46 vs. I used to run 1.275v and 4675 (4700 got unstable in Aida) on an AsRock board.
I have an Asus an dit does the same thing with my 5600x if i try to run an all core OC.