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.

There’s another little twist that lets us add a third set of numbers to our comparison here. Mainly, GeForce GTX 275s run at faster speeds than the core/shader/memory used on the GTX 295. So, in order to make a straight comparison, we actually have to down-clock our reference cards to sync up with Nvidia’s fastest offering. Allowed to operate at their default speeds, though, we’d expect the GeForce GTX 275s to be faster.

That’s great news for the gamers who were originally eying a single GeForce GTX 295 and not necessarily planning to spend another $500+ on a second board for quad-SLI. It’s even better when you start taking a look at the current state of GeForce GTX 295 availability (read: sparse). As of this writing, there’s only one card available from Newegg—EVGA’s $589 Red Edition board, which has been marked up exorbitantly for its Ferrari red shroud. A pair of GeForce GTX 275s, on the other hand, go for about $239 each.

So what’s the gamer with a little spare dosh in his pocket to do? Let’s dig a little farther into what makes a GeForce GTX 295 more than just two GTX 275s pasted together, along with some of the other variables you’d want to consider—like power, heat, and room on your motherboard.

Read The Full Benchmark:

http://www.tomshardware.com/reviews/...-sli,2298.html