Windows 7 QueryPerformanceFrequency returns 2.4 MHz ish?

I use some time code for different OS. I notice the following patterns with QueryPerformanceCounter results

Standard Windows XP uses the processor frequency, which means that it uses RDTSC under the hood.

Vista uses HPET, 14.318.180 Hz

Any version of Windows with / usepmtimer uses an ACPI clock of 3,579.545 Hz

Windows 7 uses clocks of uncertain origin that return variable numbers from 2.4 to 2.6 MHz.

Does anyone know what clock Windows 7 uses by default? Why is it even slower than an ACPI watch? Is there a way to get Windows 7 to use HPET instead?