[LAU] Playing back clicks - where to dig in?

Hi! I use Kubuntu Karmic testing (will be released 29 Oct). After some upgrade I have got this problem: on high system load (say, building NetBeans from sources or other JVM-running intensive task - JVM is very greedy wrt CPU, starting multiple threads) clicks takes place on playing back (doesn't depends on player - MPD (very stable!) and Amarok using shows the same result). At first I have tried to play with different io schedulers: deadline and noop seem to be slightly better rather anticipatory and cfq, but still stutters takes place. So the problem seems to be related with CPU shareing rather hdd access. Where to dig in further? I'd like to avoid using of rt-kernel as far as I know generic one is able to be smooth wrt my situation.