Why is DiabloMiner using so much CPU now? DiabloMiner uses about one 50% of CPU on my system (distributed among 2 cores). I could have sworn that it used almost no CPU (1-2% max) in older versions, but I'm not really sure if I should report this as a bug or not. So, is it normal, or am I correct in remembering that GPU miner should not use more than 1-2% of CPU while mining?

Link: Possibly related question.
It almost certainly is related to the question you linked and it almost certainly has the same answer I'm sad to say. There is a lot of this going around and no one is really certain what exactly is causing it.

There have been reports that ATI's 11-7_vista64_win7_64_dd_ccc_ocl drivers often bring the problem about, and reverting back to an 11-6 version seems to fix it. Not sure if it will work for you or if it even applies to your situation but it's worth a shot.