other info:
I Have currently installed a: Geforce 4 ti4600
I am using the latest VIA Chipset drivers: VIA_HyperionPro_V524A (4 in 1 which includes agp drivers)
According to Chapter 4, page 4-22, your motherboard supports 8x. It will probably default to that setting; however, if not you can enter the BIOS and arrow over to "Advanced" and look under "AGP Mode". If it doessn't show 8x, you can go into "Configuration Options" and change it from 4x to 8x.
You said you were running a TI4600? I still have that card in one of my old AGP builds. It's a great card and extremely reliable! To confirm your thoughts, the TI-4600 is only a 4x card...... You can throw it in an 8x agp slot, but it won't run at 8x.....