Intel CPUs use turbo boost to reach the highest multiplier. Turbo boost is controlled by a long and a short power limit. If these limits are not set high enough in the bios, your CPU will throttle and slow down when overclocked and fully loaded with Prime95.
When overclocking, some motherboards will set these power limits to unobtainable values like 4095. Your Core Temp screenshot shows that your CPU is being limited to the 95 Watt TDP value.
You can run HWiNFO and it will show you the reason that your CPU is throttling.