Value and ConclusionSecond helpings don't always taste as good. At $400, a pair of GeForce GTX 960 cards in SLI makes you QHD (2560 x 1440) ready much in the same way as mid-range graphics cards from a few years ago made you Full HD ready, up from such low resolutions as 1680 x 1050.
All by itself, the GTX 960 SLI is a cracker of a combination, and we see performance upscale in excess of 80 percent in games that take advantage of SLI, at 1080p and 1440p resolutions. Far Cry 4 sees its 1080p frame-rates almost double, while its 1440p frame-rates go from a barely-playable 30 FPS to a fluid 60 FPS. There are also games where the scaling isn't as profound, as with "Batman: Arkham Origins." Those would be titles that are encroaching on the CPU-limit, and in which you're above 60 FPS with a single card. Then there are those games with zero upscaling, such as Assassin's Creed: Unity, in which developers haven't gotten around to SLI optimization.
Since this is our first multi-GPU review after new-generation consoles settled into the market, we noticed a worrying trend in game engines (particularly with cross-platform games for new-generation consoles) where deferred rendering doesn't take advantage of multi-GPU setups; in games such as Dead Rising, Assassin's Creed: Unity, or Ryse. A tell-tale sign of such an engine would be the lack of MSAA support. That could spell trouble for not just a SLI setup with affordable graphics cards as it could also hit NVIDIA's enthusiast-grade multi-GPU market hard, including its flagship dual-GPU solutions.
The GeForce GTX 960 SLI is not just undone by its own shortcomings due to a lack of perfect scaling in some games, but in being a whole $70 costlier than a single GeForce GTX 970. The GTX 960 SLI ends up offering roughly the same average performance as a single GTX 970 across resolutions. You're, hence, much better off choosing a single GTX 970 to GTX 960 SLI; that is, if you plan on buying two of these cards outright. The GTX 970 offers close to 20 percent more performance per dollar than the GTX 960 SLI in 1080p and 1440p.
The narrow 128-bit memory interface per card and low 2 GB per GPU memory let the GTX 960 SLI down, particularly in higher resolutions. In a multi-GPU scenario, an app is dealing with dedicated memory the size of a single card (2 GB in this particular case). This is where a single Radeon R9 290 from AMD with its 512-bit wide memory interface and 4 GB of memory comes in ahead with higher resolutions. The R9 290 is just around 4 percent slower in 1440p, 8 percent slower in 1080p, and 4 percent faster at 4K Ultra HD, but a whole $130 cheaper. Granted, the card has its quirks with temperatures, fan-noise, and power-draw, but at the end of the day, it's still a single-GPU card.
Prospective buyers of a single GTX 960 would be advised to hold off on purchasing their second card until NVIDIA has cut its price by a lot. Given its various components, it wouldn't shock us if NVIDIA can sell this card for half its current price. By then, single GTX 970 cards would have become cheaper as well.