Whenever I close Cudaminer (2012-02-28), my system becomes extremely sluggish (Win 7 x64). I was going to say that it seems to be MSI Afterburner that is the culprit but that might not be true. Before running Cudaminer it doesn't take up much CPU resource but after quitting Cudaminer, it fluctuates between 10 and 99%. Beforehand it's no more than 4-6%.

Here is the CPU usage after a fresh boot. It settles very quickly and stays low:



And this is minutes after I've closed Cudaminer *and* MSI Afterburner. Lots of spiking to 99% but it doesn't appear visible in the process list from what I can see.



The CPU is a single core AMD 2.8GHz Sempron but they run perfectly well with cgminer/sgminer/vertminer and AMD cards.

Any ideas?