I got some information from some other threads, e.g.:
http://forum.bitcoin.org/index.php?topic=6188.60As far as I know the problem occurs when:
a) more than one graphic card is installed
b) occurs with crossfire enabled and disabled
c) is particularly bad when only one cpu core is available
d) might be related to SDK 2.4 (in one of the other threads someone mentioned that this might not occur when SDK 2.1 is used, so you would need to use catalyst 10.4 as far as I know)
It seems that a lot of people don't realize that problem because they have multi-core cpu's, e.g. a six core cpu with 2 graphic cards would only use 2/6 => ~33% of the cpu usage, although the problem is the same.
I do have the same issue. I tried the SDK 2.1 alternative once, but got the same results - however, I didn't clean all drivers with drivesweeper so it might not be bulletproof - maybe someone can respond on that one.
Anyone ever tried winThrottle ?
http://www.oldskool.org/pc/throttleIt seems to be an old software but was (besides affinity and granola) the only cpu throttling software I have found. Problem is you need to install the included drivers as a Windows device but Windows 7 doesn't let me (cannot add manually a device - maybe I'm just to stupid to find a way - do you know one on W7?). The idea would be to max the overall CPU usage to e.g. 20% (or lower). Even though mining software would still use those 20%, it would be far better. What do you think?