How do they detect RAM and CPU frequency?

Hello.
I'm writing a small program for Windows which shows some hardware info. I want to add frequency detection, but I failed to find out how it is done.
At the moment I use WMI. The Win32_Processor class has field CurrentClockSpeed, but it reports incorrect values.
Also I want to add RAM speed detection. I have searched for this topic on the internet but found nothig. Does anyone know how to do this?
I will appreciate any help.
Thanks in advance.

P.S. WMI gives me correct system bus speed but I can't use it for I don't know CPU or RAM multiplier...

P.P.S. Link to a forum where I can ask this question would be great, too.