Can I upgrade my graphics card?

I want to upgrade this to the latest NVIDIA cards. Is this possible and what are my options.

Your Mac Pro uses EFI-32, so the latest NVIDIA cards won't work. You can use the ATI Radeon HD 4870
<http://store.apple.com/us/product/MB999ZM/A?fnode=MTY1NDA5OQ&mco=MTA4MzU2NTc>
(Despite what Apple says, it will work in any Mac Pro.)

If you insist on NVIDIA, you can use the GeForce 8800 GT
<http://cgi.ebay.com/1st-Gen-Mac-Pro-nVidia-GeForce-8800-GT-512MB-Video-Card-/31 0212307192?cmd=ViewItem&pt=PCC Video_TV_Cards&hash=item483a1828f8#ht_3078wt965>
Be sure to get the version made for the pre=2008 Mac Pro.

If price is not a concern, there is the Quadro FX 4500
<http://www.welovemacs.com/6613928r.html>

The options are which compatible cards are available from the Apple Online Store. Right now your options appear to be:

EVGA GeForce GTX 285
NVIDIA GeForce GT 120 Graphics...

I do not believe the first card will work in your model, but the second one should. You might check at Bare Feats for additional information on machine compatibility and benchmarks.

This card, ATI Radeon HD 4870 Graphics Upgrade... is compatible with your computer. If you don't want to spend that much, then look at the ATI 3870 HD Mac/PC Edition which Apple no longer sells. However, you may find them available at macsales.com as well as on eBay. A Google search may scour up other vendors. Also on the obsoleted list would be the Nvidia 2600HD card but you must find one specifically for the Mac.

There are no Nvidia cards available that work with 1,1.

The two mentioned require 2008 or later (3,1 and up).

Of course nVidia GeForce 8800GT 512MB PCI-E card works with the Mac Pro 1.1. Just make sure you get the appropriate card as it comes in two versions for 1.33GHz and 1.66GHz system bus speeds.