Maybe some people with more experience can help me. One time my 10900k can do legacy 03 7100 with 1.74v without problems and can do 6.9Ghz 10c/18t 06. Second time cpu can do 06 but can't do 03 on 7100. Try with higher and lover Vcore change, PLL bandwidth, PLL voltage from 1.6 to 1.65 nothing help. First test when CPU can do 7100 03 use gts 450 and second time when crash 7100 use radeon VII card