Where did you obtain a binned CPU without being delidded?
I would suspect maybe get better TIM and check the mono block mount, they inherently cannot give as good contact as a CPU only block. I admit they do look very nice
4.5 GHZ is a very good 24/7 overclock for a 7920 - 7980 if you have the cooling capacity, don't forget to set AVX and AVX 512 offsets