HardwareZone takes a look at AGP4X and AGP8X to see if there is any real benefit for you.
At the chipset level, there are only a handful available today. If you're looking for an Intel-based solution, there's only the VIA P4X333, VIA P4X400 and SiS648. Intel does not yet have any announcement for chipsets supporting AGP8X but we have heard that the upcoming Granite Bay would support AGP8X. Over at the AMD camp, you should look out for VIA's KT400 or NVIDIA's nForce2 chipsets - both of which will support AGP8X and DDR400.More information at HardwareZone