I had the same thing. My frame rates were quit solid no matter how busy the area was. After the patch, my frame rates dropped, and I had pauses in a busy area.
I copied the HTC folder, and deleted everything. I downloaded a fresh full install, and re-installed everything including a new high res, and skins install. I think put back my Settings folder, Sights, and ahiiterr folders.
This did the trick and my frame rates were normal. About the only thing different I notice is I now have the default sounds. It may be possible that it had something to do with the sound files.
Gunner