To disable that annoying automatic clock throttling (downclocking) on the latest Intel CPUs, you have to disable two features in your BIOS: C1E and Speedstep (EIST). However, if you are stuck with some cheap-ass motherboard and you cannot find these options in your BIOS, you can workaround it by using software called
RMClock, but you will have to put RMClock on startup.