Comment 10 for bug 455112

@Michał Gołębiowski: I can confirm that this problem didn't exist in Jaunty where Virtualbox ran very well with SMP (2 cpus) enabled (and, of course, VT-x which is required for SMP). I have an Intel Core2Duo E8400 with 3 GHz.

Now under Karmic the situation is considerably worse: With SMP enabled, VB runs very slowly on my machine. Going back to 1 cpu and leaving VT-x enabled improves the performance a bit (but still not comparable with Jaunty), and disabling VT-x makes it worse again.

So something has changed in Karmic under the hood and not for the better ...