The guys over @ Ocaddiction.com have posted a guide which takes a look at AGP 8X performance! Here's a snip.
AGP 8X technology has recently been introduced by NVIDIA, ATI and SiS for improved performance on their current video card solutions. These companies are consistently striving to increase video performance in the state of the PC industry. More bandwidth, higher throughput, higher utilization, faster core and memory speeds, smaller die size. Anything possible to gain an edge over the competition. SiS was the first company on the scene to introduce an 8x AGP capable video card (the Xabre 400) and all other companies have consequently followed suit. We are still waiting for the chipset industry to fully adopt the new standard but it surely won't be long. SiS was again first on board and will soon be joined by Intel, VIA and AMD who have plans to fully support AGP 8X in their chipsets as well.
AGP 8X A Closer Look
AGP 8X technology has recently been introduced by NVIDIA, ATI and SiS for improved performance on their current video card solutions. These companies are consistently striving to increase video performance in the state of the PC industry. More bandwidth, higher throughput, higher utilization, faster core and memory speeds, smaller die size. Anything possible to gain an edge over the competition. SiS was the first company on the scene to introduce an 8x AGP capable video card (the Xabre 400) and all other companies have consequently followed suit. We are still waiting for the chipset industry to fully adopt the new standard but it surely won't be long. SiS was again first on board and will soon be joined by Intel, VIA and AMD who have plans to fully support AGP 8X in their chipsets as well.
AGP 8X A Closer Look