video hesitation (possably)

I use a 1Gb AMD Athlon, 256K PC133 SDRAM, Asus A7V Mainboard, NVidia AGP 32Mg Model 64
graphics adapter, and a 400Wt power supply, AMD Approved, and run Win ’98 SE. After about 2 hours of use, it starts to hesitate when it goes into using the 3-Dsoftware. Is there a conflict with this mixture. I’m thinking the video card isn’t fast enough.
Thanks for your help.