What I did was just the normal 'Task Manager fix' (setting priority of FalloutNV.exe to High) but I also changed the priority of steam.exe to low and that fixed all of my issues. No Silent Hill fix required and you can play the game with AA and HDR!

Hope this helps

sounds interesting. can you pls explain where and how this is to be done? thanx....

when you start New vegas, just fire up the task manager (ctrl + alt + del) and raise the priority of FalloutNV.exe to high and that of steam.exe to low.