Hey guys, I'm playing the game on the following setup:

Gigabyte GTX 460 1GB
AMD Phenom II X4 955 @ 3.2Ghz stock
4GB Ram
W7 64-bit

I'm playing the game at ultra setting with 2x AA and 15x AF. I applied the dll lag fix, and generally I'm getting 60-65 FPS, but whenever I'm looking at the NCR correctional facility, my FPS suddenly drops to 40! And when I had the big fight over there involving Eddie and the baddies, my FPS even dipped below 30. I have this same problem in Nipton, once I arrived for the first time my fps dropped to 40-45. I'm guessing this has something to do with the amount of NPCs present.

Can anyone enlighten me, should I be getting a more steady FPS with my rig? Someone with a similar rig who can tell his experiences with the FPS?

EDIT: Okay I ran some tests with several savegames, it seems that NPC faces are still causing slowdown for me, whenever I'm seeing lots of NPC faces at the same time, FPS drops by ~20, less than before, but still there. Lagfix done wrong? Anyone else who has this?

I have an intel e4500 2.2 dual-core but other than that i have the same specs as you.
I have the same drop in Nipton and micro stutters cause the framerate to drop to about 20 at some points for a brief moment. I also have the same problem at the NCRCF as well. it's probab;y just our rig. hopefully a new patch will come soon to help the lag issues around buildings and cities.