Crossfire meets PCI Express 2.0 – More Lanes, More Frames?

PCI-Express-2.0 Crossfire PCI-Express-x16-x8-x4 The most frequently asked question on forums these days deal with the new PCI Express 2.0 interface. Is Intel’s P35 chipset good enough, or is the X38 the better choice? How much more performance can you expect from an upgrade? Do current graphics cards even really take full advantage of the PCI Express interface?

Recently, we’ve received some critical reader feedback saying that using an Intel 975 chipset with its “castrated” PCIe interface to test a modern dual-card HD38x0 setup could no longer be considered up-to-date. We’ve taken this suggestion as an opportunity to switch our lab over to newer hardware, so that all future ATI Crossfire testing will be conducted on motherboards using the X38 chipset (Thank you so much kind and critical readers! Ed.). To determine what benefits this changeover actually brings us, we have run a few specific tests that focus on Crossfire resolutions that actually show a performance improvement. In the best case, we got 20 percent more 3D performance out of our Crossfire setup.

In this test we included all current graphics cards using the PCI-Express 2.0 interface such as the Nvidia’s Geforce 8800 GT and 8800 GTS 512 as well as ATI’s Radeon HD 3850 and 3870 cards. We also decided to test the HD2900XT. Even though it’s still a PCIe 1.1 card, it remains ATI’s fastest offering, making it an ideal choice to compare the performance results between the old and new testbed platforms.