Here are screenshots for OC+xmp and Stock+xmp. As you can see Stock results is much better then overclocked. After disabling virtualization in Bios, everything starts work how it should and OC result is better then stock. So the problem in Virtualization technology (or judging other topics maybe the problem is in Windows sandbox feature since it uses Virtualization, but I already disabled Virtualization in Bios and don't want to restart PC just for checking this theory).