SLI Is Coming: Time To Analyze PCI Express

PCI Express Mode Examination With SLI Pending

This past June, Intel released the PCI Express chipsets 915P and 925X, while the Athlon64 world still must wait for suitable platforms from ATI, NVIDIA or VIA. The introduction of PCI Express has not been a big deal so far, because DDR2 memory and PCI Express graphics have thus far failed to deliver the expected performance boost. The bottom line is that right now, there is basically no real difference between newer AGP systems and those using PCI Express. One major reason is that even the latest 3D games rarely need bandwidth that is 4 times faster than AGP 8X.

That said, it would be rash to say that the new interface is unnecessary. PCI Express has already proven beneficial for professional hardware, and future 3D games and applications will continue to become more realistic and eventually will need more bandwidth.

The question of how much bandwidth future graphic interfaces will actually need remains. In order to answer this question we played around for a little while and tested all the possible link speeds of PCI Express: x1, x2, x4, x8 and x16. To find out which of the current graphic technologies depend most on available bandwidth, we tested ATI's Radeon X800XT and NVIDIA's GeForce 6800 GT. The answer will be useful when we consider the needs for future SLI-enabled systems.