Here is a link to the only place I use for complete technical and user data priot to upgrade.
http://www.tomshardware.com/index.html
Here is the summer 2005 index.
http://graphics.tomshardware.com/gra...705/index.html
Here is the latest from nvidia. Man, the things I could do with $500+ dollars, just to be king of the hill for a few days!
http://graphics.tomshardware.com/gra...221/index.html
Could you post your PSU numbers?
Total watts?
Amps from your 12V rail?
This can be found on the stick/label of your PSU (power supply unit). You will have to power down, remove a side, and possibly either contorsion yourself to read it, or just loosen the screws and manipulate it enough to read it.
Should be something like
12VDC Amp 18A. From there we can maybe help with your overall situation.
Here is a link to Toms about picking a PSU, it's a yera old, but the info is valuable.
http://www.tomshardware.com/howto/20040122/index.html
Hopefully we can get it figured out, and you can have a good experience.
Peace