1) Kernel sources must be installed and configured.
2) switch to runlevel 3 ("init 3")
3) Do not go to sax2 configuration, just type sax2 -m 0=nvidia (0 is a digit, not a letter!)
4) Sax still will ask you to configure your monitor, etc. just cancel out of that and startx.
NOTE: you might want to reboot before starting X-windows. I had to because my system gave me a font error.
5) When you see Nvidia splash screen while starting X means nvidia drivers enabled and you have 3D support.
6) Bottom line you don't have to enable 3D in sax2
Mobo: Shuttle AK266-A
CPU: AMD XP 1800 @ 1750Mhz
HDD: WD Caviar 40Gig
HDD2: IBM 50Gig
Video: GeForce4 Ti4200
DVD: Sony 16X
CDR/W: Creative 40x16x8
Case: Antec 1080B 350watts
Ram: 512Mb PC 2100
OS: Suse 8.1