nVidia AGP module
Fast Writes and Side-Band Addressing are off by default, you must manually enable them when desired, but you shouldn't until the card is operating stably as they can cause problems. The gains associated with these options are minimal, but worth using when the card is stable.
You should try using the nVidia kernel AGP driver rather than agpgart. Add this option to your XFree86 config, in the Device section for your video card:
Option "NvAGP" "1"
For many mobos the nvidia agp module is more stable than the agpgart module, afaik you just have to try both and see how it goes, however there are some listed / known reasons to use one or the other in the nvidia readme.
"..the triumph of evil is for good men to do nothing."
VIDIA video driver RPMs for Fedora
:: see yum repo at livna.org