I think I found the problem. Back when I was using the old processor, I compiled
3.6 with -march=k8. But when I switched processors I didn't think to recompile.
After recompiling with -march=barcelona, I got a 40% speed increase with 3.6!
The configure script for 3.7 uses -march=native so I think that might account
for why it seemed to be so much faster.
