If you want the new GeForce GTX480 card, but don’t have a motherboard that’s capable of the new PCIe x16 standard, you might think it’s beyond your means.  Many people don’t realize that the PCI-Express system is comprised of multiple independent data-paths, called “lanes” by many, and that while the GeForce GTX480 uses all 16, it still works with fewer.  Surely there’s a huge performance penalty, right?  That’s what TechPowerUp set to find out:

To maintain its speeds, it would hypothetically require high system bandwidth, leading one to think that lesser PCI-Express configurations would cripple it. The theory couldn’t be more wrong, as seen by the mere 2% performance loss going from x16 to x8 (which reduces bandwidth by 50%). To cite results from one of the latest and resource-heavy games in our bench, Collin McRae DiRT 2, that translates into something like 63.2 FPS vs. 62.1 FPS, at 2560 x 1600 pixels resolution – barely a difference.
We also examined how much PCI-E 2.0 x4 (or PCI-E 1.1 x8, older motherboards) would affect the GTX 480. And the result coarsely put is “not much”: 8%.

Less than 2% difference when dropping it from x16 to x8.   While you realistically wouldn’t run a card like that, it does bode well for people who want to run the card in SLI configurations, where it proves that the card is not starved for data.

techPowerUp :: GeForce GTX 480 PCI-Express Scaling Review :: Page 1 / 25.