Hey I normally run Core Temp in the background to keep an eye on my temps. but the other day I noticed that CPU-Z says that my CPU frequency is at 1.6ghz in idle while Core Temp says it's at 2.1ghz during idle. I'm running the latest version of CPU-Z although I think Core Temp may be slightly out of date. It also says my bus is increasing in halfs like 8x, 8.5x, 9x, 9.5x etc. My CPU is the Intel Core 2 Duo E6700 @ 2.66ghz which was upgraded from a Duel Core Pentium E2160 @ 1.8ghz, idle 1.6ghz.
CPU-Z: 1600mhz (266x6)
Core Temp: 2.1ghz (266x8)
Note: there seems to be less variations on CPU-Z on the multiplier and it say the multi is always either x6 or x10