How time flies. The last time we had a bleeding-edge graphics card from NVIDIA to try by fire, was exactly a year ago, with the launch of GeForce GTX 590. Quite a bit changed since then. Rival AMD is just about done with the launch of its Radeon HD 7000 series "Southern Islands" GPU family, and NVIDIA's answer to that felt wanted, for the past 3 months or so. Well, it’s finally here – our GeForce GTX 680 Kepler review.
Both evolutionary and revolutionary changes have gone into making the GeForce GTX 680. It's evolutionary in that it's designed to be an upgrade over its immediate predecessor (and not something two generations behind), and revolutionary new features make sure GTX 680 is a worthy upgrade. The evolutionary part of course is that NVIDIA wants to reclaim the title of having the fastest GPU out there; and the revolutionary part is a vibrant feature-set that supposedly contributes to never before seen energy-efficiency levels, to accomplish those steep design goals.
Product PositioningSpeaking of positioning, NVIDIA is gunning for nothing short of the performance-crown for single-GPU graphics cards, with the GeForce GTX 680, and it wants to do so without having to compromise of energy-efficiency. In the past, we have seen both NVIDIA and AMD throw energy efficiency to the wind and come up with power-guzzling chips, in a blind pursuit of performance leadership. That's not the case with GeForce GTX 680.
See what we mean? To be fair to the HD 7970, it did impress us with its performance/Watt figures. What NVIDIA is looking to do is raise the bar with energy-efficiency. To accomplish that with the Kepler-based GTX 680, and go on to seek performance-leadership is a very tough ask, and takes some very gritty engineering.
One revolutionary change that allows GeForce GTX 680 to aim high, is an extremely smart self-tuning logic that fine-tunes clock speeds and voltages, on the fly, with zero user intervention, to yield the best possible combination of performance and efficiency for a given load scenario. The GTX 680 hence reshapes the definition of fixed load clock speed, with dynamic clock speeds. Think of it as a GPU-take on Intel's Turbo Boost technology, which works in conjunction with SpeedStep to produce the best performance-per-Watt for CPUs that feature it.
|Shader Units||1280||512||1792||2048||1536||2x 1536||2x 512|
|ROPs||32||48||32||32||32||2x 32||2x 48|
|Graphics Processor||Pitcairn||GF110||Tahiti||Tahiti||GK104||2x Cayman||2x GF110|
|Transistors||2800M||3000M||4310M||4310M||3540M||2x 2640M||2x 3000M|
|Memory Size||2048 MB||1536 MB||3072 MB||3072 MB||2048 MB||2x 2048 MB||2x 1536 MB|
|Memory Bus Width||256 bit||384 bit||384 bit||384 bit||256 bit||2x 256 bit||2x 384 bit|
|Core Clock||1000 MHz||772 MHz||800 MHz||925 MHz||1006 MHz+||830 MHz||607 MHz|
|Memory Clock||1200 MHz||1002 MHz||1250 MHz||1375 MHz||1502 MHz||1250 MHz||855 MHz|