2.6.38 should contain a ~200 line patch that makes a huge difference to desktop responsiveness under load; "Tests done by Mike show the maximum latency dropping by over ten times and the average latency of the desktop by about 60 times" Ref: http://www.phoronix.com/scan.php?page=article&item=linux_2637_video&num=1
And a RedHat dev reckons you can get the same via configuration; Ref: http://www.webupd8.org/2010/11/alternative-to-200-lines-kernel-patch.html I havent tried it yet...
