So, do three GeForce GTX 660 Ti cards in three-way SLI offer more high-end gaming value than two GeForce GTX 680s in SLI? A simple chart comparing graphics price to performance would appear to show that two GeForce GTX 660 Ti boards in SLI offer the best possible value, followed by a single GeForce GTX 680 2 GB at reference clock rates. Every other combination of cards is going to cost you more than the performance it enables.
On the other hand, gaming at the highest resolution possible was the goal of today's testing, and we're happy to say that we were able to run all of these configurations at 5760x1080. Even then, the sun shines brightest on Nvidia's GeForce GTX 660 Ti.
We could minimize the impact of the graphics card by factoring in the total cost of our platform, but today's testing wasn't about platform analysis (like what you saw recently in FX Vs. Core i7: Exploring CPU Bottlenecks And AMD CrossFire). We doubt the expensive Core i7-3960X was even a benefit in today's tests. We wanted to use it to help mitigate any argument about four-lane PCI Express links that we would have encountered if we used an LGA 1155-based setup. If we were spending money though, we probably would have used an overclocked Core i7-3770K instead.
The issue we have with the GeForce GTX 660 Ti’s apparent performance wins is that the average frame rates don't account for the few times we ran into problems. For example, the super-high resolutions we'd want to use after spending close to a grand on graphics didn't work properly on any graphics card with 2 GB in F1 2012. The 3 GB models that might have helped solve this issue would have stepped us up from $290 per board to $320.
None of these configurations were able to cut through our most demanding Metro 2033 settings (not particularly surprising; Metro remains a complete bear, even for high-end hardware). But GeForce GTX 680 cards in SLI played through those high-quality settings most smoothly at 4800x900. Similarly, both GeForce GTX 660 Ti-based configurations suffered occasional slowdowns in Battlefield 3 that could make the game unplayable at 5760x1080 and Ultra Quality.
So, while three GeForce GTX 660 Ti cards in SLI are both cheaper and faster on average, there are a few instances where they simply cannot offer an optimal experience at 5760x1080. Running two GeForce GTX 680 cards in SLI improves two out of three situations we flagged, and 4 GB of GDDR5 memory solves the third. Given those observations, Gigabyte appears wise to have sent us the 4 GB version of its overclocked 680.