Part of being a PC enthusiast is seeking out the sweet spot—that perfect intersection of features, performance, and price. We tend to look for the best value when our money is on the line. At the same time, though, there's something to be said for basking in the glorious excess of truly extreme setups. If you thought one GeForce GTX 680 was impressive, wait til you get a load of four. Dutch site Hardware.Info has put together a quad-GTX 680 review that includes three- and two-way SLI configurations in addition to a boatload of CrossFire setups based on the Radeon HD 7970.
Multi-GPU setups haven't always scaled gracefully beyond two cards, and it looks like threesomes might still be problematic. Hardware.Info encountered stability issues and compatibility problems with its three-way setups, but the quads were apparently trouble-free.
In 3DMark11's Extreme test, the four-way setups offer 3.6-3.9 times the performance of a single card. However, in-game frame rates don't scale as linearly. While the quad setups tend to offer the highest FPS with the most demanding settings, they're far from doubling up on the duallies. As one might expect, the degree of performance scaling, and whether the GeForces or Radeons come out ahead, very much depends on the game.
Hardware.Info astutely points out that four-way setups are really only useful for setting benchmark records. A single high-end graphics card should suffice for most folks, including those with monster monitors.