Vanguard SoH performance question

I've read lots of post and lots of forums and a lot of people seem to have the same performance issues as myself. But we all share one thing in common, we all own nvidia cards. I'm trying to find out if anyone that plays Vanguard SoH with a decent ATI card has the same performance issues as myself. I usually play on balanced and average mid 30's FPS outdoors with 2 characters. A full group is just horrible on balanced. In town is rough with 12 - 20 FPS on average.

The performance issues are having low framerates when they should be higher or getting great framerates in one area and then they drop to the floor for no graphical reason. My system is:

E6600
2GB ram
8800 GTS
gigabyte-ds3
raptor 150gb x2

I have no problems playing other games, and just want to see if people with ati are having the same framerate issues as myself.