Yesterday, AMD released their new Catalyst 11.2 drivers. Radeon 6000-series owners will find that the 100% GPU usage bug at idle has been entirely fixed. Radoen 5000-series owners sadly still have this problem, but it seems to only affect some people that make use of Firefox 4 and/or Flash hardware acceleration.
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This driver's quite a step up from 11.1 and I highly recommend updating to it, particularly if you have a Radeon 6000-series GPU. Remember to disable Firefox 4 and/or Flash hardware acceleration when updating to this on a 5000-series GPU or your performance will suffer!