On Mon, March 4, 2013 3:26 am, Gabbe Nord wrote: looking through the output of dmesg or /var/log/syslog should show if the cpu has hyperthreading and how many cores there are. Hyperthreading should not be a problem down to running jack with -p64, but it does make a difference going lower... it may help make -p64 more stable too. If you have hyperthreading this can be turned off by disabling every second cpu. That is if you have a single core system with hyperthread, you will have cpus 0 and 1, disable cpu 1 as it is really just the hyperthread on the same cpu. Just to be sure... you are not by chance using a wireless networking IF? I have one that gives xruns even at -p1024 :P -- Len Ovens www.OvenWerks.net