RMClock, short for RightMark CPU Clock Utility (formerly known as AMD64CLK), is software developed by iXBT.com, distributed under the brand RightMark Gathering. A free version is available as is a licensed "pro" version.
RightMark CPU Clock Utility (RMClock) is a small GUI application designed for real-time CPU frequency, throttling, load level monitoring, and on-the-fly adjustment of the CPU performance level on supported CPU models via the processor's power management model-specific registers (MSRs). In automatic management mode it continuously monitors the CPU usage level and dynamically adjusts the CPU frequency, throttle and/or voltage level as needed, realizing the "Performance on Demand" concept.
RMClock is confirmed to work on Windows XP, Windows Vista, Windows 7. Currently RMClock only supports the 64-bit versions of Vista and Windows 7 in a limited way.
The last version was released in 2008 and no further development has been undertaken.