I can't speak for the OP, but I was hit by this bug with an almost identical CPU setup (Xeon x5355) and the kernel in proposed doesn't resolve the issue for me. The upstream utopic kernel link posted at #7 however does fix it. My symptoms are identical.
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1386473 Title: Not using all cores after upgrade to 14.10 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1386473/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
