the turbo feature seems to be active the multiplier should only be 20 for that chip.
unfortunately I don't know exactly how to return it to normal on your system.
...it really shouldn't be causing any problems though as the turbo feature is provided by intel themselves. It's basically built into the chip itself.
While I try to figure this out it wouldn't hurt to reinstall the chipset driver
from asus ASUSTeK Computer Inc. - Desktop- ASUS Essentio CG5290
(make sure win 7 x64 is selected in the dropdown)
There are a number of bios updates for your system.
Bios updates can be a tricky thing though, if you've never updated a bios before make sure you read the directions very clearly and know exactly what you are doing before hand.
Bios updates are inclusive meaning you'll only need to install the most recent one.
This may in fact solve your problem as all the updates are system stability related.