Hardware specifications SW

Speccy
HWMonitor 
CPU-Z

The CPU-Z's detection engine is now available for customized use through the CPUID System Information Development Kit, a professional SDK built for the Microsoft Windows operating systems. 

1 CPU-Z reports my CPU running below its clock specification or the clock speed is varying.

This is the effect of the CPU power reduction mechanism : C1E (Enhanced Halt State) and/or EIST (Enhanced Intel SpeedStep Technology) for Intel CPUs, Cool'n'Quiet and or PowerNow! for AMD CPUs. Load your system and you will see the frequency increase to its nominal value.

2 CPU-Z reports a wrong CPU vcore.

Please download HWMonitor then save monitoring data (menu file -> save monitoring data) and send back the file to that e-mail address.

3 CPU-Z causes a general protection fault, or freezes my system, or causes a blue screen.

edit cpuz.ini, and replace:
DMI=1
Sensor=1
SMBus=1
Display=1
UseDisplayAPI=1
with:
DMI=0
Sensor=0
SMBus=0
Display=0
UseDisplayAPI=0
Then run cpu-z again. If it works, restore the "1" one by one, until the problem occurs again. Then send an email and mentioning which "1" is responsible.

4 Why does CPU-Z misreport my memory module specification ? For example, my DDR2-800 is reported as DDR2-667.

The memory theorical bandwidth is computed using the module access time information for the maximal CAS# latency value, included in the SPD area. If the computed bandwidth is lower than the one specified on the memory module, that means that the SPD information on the module is not correctly programmed, or most likely that the bandwidth is not given at the default memory voltage, but at a voltage defined in an extended profile (EPP or XMP).