I have the newest version of the Nvidia Linux driver (not from repo's) installed on my Ubuntu 8.10 (64bit) box and I am having serious performance issues. Here are my specs:

AMD Quad core 9500
6GB Ram
Nvidia 8800gt
Ubuntu 8.10 64bit (up to date as of today)
Driver - NVIDIA-Linux-x86_64-177.82 (NVIDIA driver NOT from the repo's)

When I am playing any 3d games (Nexuiz/OpenArena) I get a real slow down in FPS and the graphics look to be "choppy".... In all games I am getting a bit of jitterness or delay. It's weird because I used this card in a much lower end box that had half the RAM and only a dual core AMD 64 (that was on Kubuntu) and it was BLAZING FAST on maxed out settings.

I did try all of the recommendations listed in Nvidia forum and here but nothing seemed to help.
http://www.nvnews.net/vbulletin/showthread.php?t=118088 As an aside I did try an earlier driver from the repos and it had the same issue so I am sticking with this.

Does anyone have any suggestions?

Thanks in advance!