Comment 29 for bug 579117

Well, I'm also out of really good ideas, but if you have the time, I guess you just have to continue investigating and trying combinations of what causes high latencies and what don't. E g trying Karmic with a different kernel, trying a preemptive kernel, a mainline kernel, etc.
If you find one kernel that works and one kernel that doesn't (and nothing else is changed), you can continue using "git bisect" to find the exact commit causing the error. I'm quite certain the error is kernel related.

As for pulseaudio, if tsched=0 does not help, I don't think anything else will - but don't take my word for it, feel free to try whatever you want.