Nvidia GeForce GTX 780: Tech SpecsAs mentioned above, the GeForce GTX 780 uses a GK110 GPU as already seen in the GeForce GTX Titan. It's also based on the same Kepler architecture that Nvidia introduced with the GeForce 600 series, although the number of stream processors has been upped to 2304 compared with 1536 for the GTX 680. An instruction set for GPGPU (General-Purpose processing on Graphics Processing Units) is onboard too, so the graphics card can help out with certain other processing tasks.
The 2304 stream processors run at a nominal clock speed of 863 MHz. However, the GTX 780 comes with GPU Boost 2.0 technology, so the GPU clock can be set to vary in relation to criteria such as power use or temperature.
Nvidia therefore doesn't give a maximum attainable clock speed for this card, instead promising a minimum of 902 MHz. In our test set-up, the GTX 780 we reviewed reached up to 1006 MHz during the first few minutes of gaming. After that initial "warm-up", the clock then varied between 928 and 993 MHz depending on the game. Note that not all GTX 780 cards will reach these exact speeds, as Nvidia's system allows a certain degree of variation from one model to the next.
It's often possible to reach higher clock speeds using one of the utilities commonly supplied by graphics-card-makers. Nvidia gave us Evga's utility with our test card, which meant we could play around with the power target and temperature target (see below). With a few tweaks, the card can be made to run a little faster, although it in turn uses a bit more power and gets slightly noisier.
Like in most GeForce GTX 600 cards, the 3 GB of onboard memory is clocked at 1502 MHz. However, it has a 384-bit bus like the GTX Titan, rather than the 256-bit memory bus used in the GeForce GTX 680 and GTX 670 (among others). The GTX 780 therefore has a higher bandwidth.
SIZE & NOISE
The GeForce GTX 780 is slightly shorter than the GTX Titan (26.7 cm compared with 27.7 cm) but inherits its excellent cooling system and high-quality finish. At idle, the card's heat-management system—based around an off-centre fan—is very quiet. We measured noise levels at 32.2 dB(A), which means you have to stick your ear right up to the computer's casing to hear the fan in action.
With games, this increased to 44.8 dB(A). At this level, the fan can be heard whirring but noise levels remain generally acceptable. In comparison, the Radeon HD 7970 GHz Edition reached 56.1 dB(A) in the same test conditions, the GTX Titan was measured at 46.5 dB(A) and the GTX 680 at 47.3 dB(A).
At idle, the GeForce GTX 780 uses a similar amount of power to the GTX 680—we measured our test PC running on 50.1 watts with the GTX 780, compared with 53.6 watts for the previous model. That's also 6 watts less than AMD's Radeon HD 7970 GE, although that card does have the advantage of an advanced standby mode that shuts down the fan and keeps power use to a minimum when the screen is off.
When running games, the card's high number of stream processing units pushed up our test PC's power use to 275 watts, compared with 250 watts for the GeForce GTX 680. The GTX 780 is therefore comparable to the Radeon HD 7970 GHz Edition on power use but, as we'll see below, it beats the AMD card on gaming performances.
PERFORMANCE IN GAMES
We had to change our review process slightly with this particular card, as a problem with our test PC's motherboard meant we didn't have access to the standard set of games we use to assess performance. We'll test the GTX 780 with those titles at a later date, once we've replaced the motherboard.
However, our newer test platform was working just fine. So although we weren't able to test performance with the older set of games, we did manage to test the GTX 780 with the six new titles we've been using in reviews of more recent graphics cards. We also added a seventh game to the list—Metro Last Light—released just in time to be taken for a spin with the GTX 780. Check out the results below.
All games tested in Full HD resolution (1920 x 1080 pixels), all options activated,
with the latest updates for each game.
Once again, the GeForce GTX 780 proved similar to the GeForce GTX Titan. Performances are really very close, in fact, with an average difference of just 7% between the two models. The GeForce GTX 680 and the Radeon HD 7970 GHz Edition come in far behind, with average performances that are 32% and 25% lower respectively.
ConclusionNvidia has breathed a new lease of life into its Kepler architecture with the GTX 780. This should help keep users satisfied while waiting for the firm's new architecture to arrive, due at the end of 2013 or—more likely—in early 2014. The GeForce GTX 780 takes over nicely from the GTX 680, and although it's no revolutionary model, it puts Nvidia into a comfortable lead when it comes to graphics processing with single-GPU cards.
Competitors may only be able to rival Nvidia's card on price per performance. Still, that's something that the GeForce-maker seems to have understood, launching the GTX 780 at £550. However, with no real rival single-GPU model from AMD, Nvidia ultimately seems to be in competition with its own GTX Titan—a more expensive model that offers similar performances.