AMD's flagship graphics chip, the Radeon GTX 7970, gave us the first glimpse of AMD's new Graphics Core Next architecture. It's said to be carefully designed to work better with the gaming landscape of the future. While an important step forward for AMD's future, this initial airing for the new architecture didn't produce revolutionary results in today's titles.
With that in mind, it's perhaps unsurprising that nVidia has responded with a product that stops short of squeezing the last drop of potential from its own latest technology. Not that you'd know from the name that the Zotac GeForce GTX 680 (or the nVidia GeForce GTX 680 it is based on) is supposed to be anything but the best the company can offer - in nVidia's previous 5xx generation, for instance, the nVidia GeForce GTX 580 was very much the high-end single GPU product. See also: Group test: what's the best graphics card?
It's slightly telling that the actual chip inside the Zotac GeForce GTX 680, the GK104, is codenamed Kepler. This in keeping with nVidia's recent practice of naming its chips after significant scientists – previously we had the Fermi.
However, while Fermi was very much a key figure in the 20th century, Kepler's place in history stretches back to the early 1600s. And so the GeForce GTX 680, in some respects, fails to reflect recent advances in graphics cards, instead aiming to be a well-rounded product that takes care of the present without worrying too much about what's way off in the future.
It would be wrong to say that the GeForce GTX 680 is underpowered, but it's clear that, had it wanted, nVidia could have unveiled a product that packed more power.
Most notably, the GeForce GTX 680 must make do with a 256-bit memory interface at a time when its AMD rival (and, indeed, its own predecessor, the 580) stretches to 384-bit.
Not that there aren't some strong figures in the GeForce GTX 680. The core clock speed of 1006MHz is some 81MHz clear of the 7970 that we reviewed, and 234MHz higher than the figure produced by the original 580 chips.
The number of texture units (128) in the GeForce GTX 680 has also doubled since the time of the 580, and is now in keeping with the 7970's complement. This is significant, as the texture fillrate (the number of texture units multiplied by the core-clock speed) is a stellar 128.8GTps - a 160% increase on the 580, and almost a 9% increase on the 7970.
It doesn't look so rosy for the GeForce GTX 680's memory bandwidth, though, due in essence to the restrictive 256-bit interface. The high memory clock speed of 1502MHz is some compensation, although even with this the memory bandwidth is a disappointing 192.3GBps. This figure doesn't even beat the older 580's 192.4GBps, while the HIS version of the 7970 picked up a rather mightier 264GBps.
This here is the 2GB version of this card. There are 4GB versions available as well. 2GB should be enough for most purposes, although this configuration may look a little underpar in a couple of years time - both the 7950 and 7970 cards are coming with 3GB as standard. It's obvious, then, that nVidia could have shown us a more powerful piece of technology if it had wanted to. However, given the relatively unstartling figures turned out by the AMDs, nVidia has decided not to max out on firepower with the GeForce GTX 680, but is working instead to keep down heat and consume less Watts.
And it's very notable that, despite its relatively strong set of frame rates, the GeForce GTX 680 has a power figure of just 195 Watts. Similar figures for the Radeon HD 7970 and the last-generation GTX 580, in contrast, are 250W and 244W respectively.
In running, the GeForce GTX 680 was typically lurking in the low 180s, which is impressive given its firepower. In terms of sound levels, the 680 and the 7970 are virtually identical, although the 680 does manage to remain around 2dB quieter as the cards are really being put through their paces.
The 28nm manufacturing process helps with efficiency, as does the new architecture that doesn't concentrate as much on the high-end Compute capabilities that drove Fermi. While this might seem a retrograde step (the new architecture on the AMD 7970, after all, is specifically designed to eat into the Compute advantage that Fermi held), it makes for a more balanced chip that still remains a pretty good games player.
GeForce GTX 680: Performance
The Zotac GeForce GTX 680 was always on top in testing. In only one game title, BattleForge, was it a fraction of a frame behind the 7970, recording 68.0fps at a resolution of 1920x1200 against 68.2 for the 7970. However, in the 1680 x 1050 and 2560 x 1600 resolutions, it finished slightly ahead of the 7970, recording 80.2 and 47.7fps respectively, against 80.1 and 47.4fps for the 7970.
In all the other games the GeForce GTX 680 won decisively. In Crysis 2, for example, its figures of 45.6 and 31.2fps at 1900 x 1200 and 2560 x 1600 respectively, were significantly ahead of the 7970's 39.7 and 25.9fps.
And in Stalker it again recorded a similar lead, its figures of 86.4 and 62.1fps some way ahead of the 7970's 78.8 and 57.1fps.