Something is off...

For comparison here's my normal person rig, that doesn't have uber just came out in the last 6months to a year stuff.

E8400 Dual Core 2.9Ghz(4 years old)
GTX460 2gb RAM Vid Card
4GB RAM
Window XP(That's right, still freakin xp!)

And I run this game consistanly at 40fps, in all zones and in pvp. I can get 60-70fps in non crowded areas.

I'd try a new PSU like people have suggested, maybe its not getting enough. Though you;d think a lower power message would appear when you boot up...