Overclocking and OC Software
For overclocking and temperature monitoring, NVIDIA supplied reviewers with EVGA's latest version of their Precision overclocking utility. In this case, the newest version is called Precision X. Precision X is without a doubt, a huge departure from previous version of EVGA's precision utility and it's good to see that NVIDIA is recognizing EVGA's awesome utility which has sparked many of their competitors to do the same thing, giving consumers added value for their purchase.
When it came to overclocking the GTX 680, we had a lot of fun figuring out how to properly overclock the GPU in a way that would actually result in better performance without killing the card. The good thing is that the GTX 680 has a lot of overclocking headroom, even on the reference cooler with the reference PCB design and VRM. Considering what we were able to do to this card with EVGA's Precision X utility, there's no doubt that some manufacturers with custom PCBs and proper VRMs could easily beat our overclocks.
In order to actually overclock the GPU, you have to increase the GPU clock offset, which increases the curve by which the base clock and boost clock operate. By doing this you are shifting the curve of the power target, base clock and boost clock. But of course, you can't simply overclock the GPU frequency without increasing the power target, so we of course started to mess with that as well. After a lot of trial and error we were able to get a stable OC that was also benchable.
In our testing, we were able to get the card to run at 1,316 MHz and at that frequency we were able to benchmark 3DMark 11 in both Entry, Performance an Extreme levels. Considering the fact that the GTX 680's stock clock is 1,006 MHz we were able to overclock the card by about 30% on a reference cooler and stock cooling. This is simply astonishing for a flagship card. We have a graph below that illustrates the overclocking increases and potential of this card.
Looking at the scores, you can see that the GTX 680 without a doubt takes the performance crown from the GTX 590 and when compared to the stock clocks of the GTX 680, yields considerable performance improvements. The Extreme score of E3732 is an increase of 17 percent and the Performance score of P11133 resulting in a change of 14 percent while our Entry score of E15783 only netted 9 percent since the Entry test is much less GPU bound than the Extreme test.
Power Consumption and Heat
In terms of heat and power consumption, the GTX 680 was absolutely stellar. At idle the card ran at only 324 MHz and as a result generally consumed around 10% of TDP or 20 watts. The card would generally idle around 31C and was so cool that no warm air actually came out of the back of the card. This was the most astonishing thing about this card, normally, under idle you get some sort of heat coming out of the back of the card but the GTX 680 has NONE.
Under sustained full graphical load, the card consumed at a maximum, 186w but generally hovered more around 172w. Under these scenarios, the card got as hot as 76C and never hotter. The fan speed of the GPU also stayed extremely quiet even under heavy loads, although, we did notice that different programs loaded the GPU differently and that the temperature of the GPU did not always dictate the fan speed.
We did, against the best wishes of NVIDIA, run Furmark and were only able to get the card to peak at 80C meaning that this card is inherently very cool and for you to break 80C you've either got to be doing something crazy with terrible ambient temperatures or you've got a bad card.
Out of all the three cards we tested, the GTX 680 was by far the quietest and coolest. It was followed by the HD 7970 which was also a pretty quiet card until it got put under a heavy load, then it became both loud and hot and felt like a blowdryer. The fastest the fan on the GTX 680 ever got was 54% speed, which was handily abused by us when we set the card to 75% when we were overclocking. The card was designed to be extremely cool and quiet and NVIDIA did a great job with that. We're not even going to talk about how insanely loud the GTX 590 got under full load or how loud its idle was compared to the other two cards.
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