[LAU] ubuntu vs arch

Hi A friend of mine who would like to use his new UA-25EX with ubuntu on his (i think) x200 (at least it's a 2.4Ghz dualcore 64 bit thinkpad with 6 or so gigs of ram). A very nice machine, that should be great for setting up a linux DAW. However I cannot make it run without x-runs (did the usual limits.conf dance). Whenever a window is dragged, or there's disk activity or something like that there's an x-run. He has two ubuntus installed, a 64 bit and a 32 bit (one is natty one is marverick, forgot which is which). Both systems (mis)behave the same. I tried running in openbox with pulseaudio killed, I installed the lowlatency kernel from Alessio Igor Bogani. I've been testing with ardour (which he's probably gonna use) and renoise (which I know best). The soundcard runs great on my dualcore 1.4Ghz x61s with arch. Any ideas would be highly appreciated. NB: Exact details regarding software or hardware can be provided, but the laptop is at his place... -- Atte http://atte.dk http://modlys.dk