TH: "The GeForce GTX 275, launched last month, gives us an opportunity to run some interesting thought experiments using Nvidia's SLI multi-GPU rendering technology.
You see, the graphics processor driving the GTX 275-a 55nm mash-up somewhere between the GeForce GTX 280 and 260-sports the same configuration found in the company's GeForce GTX 295 (doubled, of course). By putting a pair of GTX 275s up against a GTX 295, we're essentially able to test one graphics solution operating over the throughput of a single 16-lane PCI Express 2.0 slot against the same arrangement running across two x16 slots.
With all of the core, shader, and memory clocks set to the same frequencies, the only real variable here would seem to be the amount of PCI Express bandwidth available to your SLI setup. In both situations, separate PCBs are attached with Nvidia's SLI connector. But the story isn't quite that simple and, as we'll see in the benchmarks, the performance results don't always reflect an advantage in one direction or the other."