ZOTAC GTX 660 Ti AMP! Edition
WHAT WE LIKED:Excellent performance, Bold styling, Low temperatures, Factory overclock, Compact PCB design
WHAT WE DISLIKED:Lack of power upgrade for serious overclocking, Pricing higher than competitors
Historically speaking, a graphics card has certain clocks, and typically they have varied for idle and load states. And overclocking a card has involved raising the clocks, and perhaps voltage for stability, to achieve higher performance. Overclocked settings are then static, and in many instances, enthusiasts would even flash their card’s BIOS to “lock in” those settings.
As we saw with the advent of GPU Boost in the GTX 680 launch, all bets are pretty much off with overclocking; it’s not the same anymore with Kepler. That continues here with the GTX 660 Ti AMP! Edition. Since the clocks and voltages are not static, overclocking doesn’t actually result in “new” clocks per se; rather, overclocking Kepler results in higher overhead potential, or targets, with many different clocks and voltages possible.
So here’s the kicker: Kepler’s “overclock” is dynamic. Others aren’t. That means Kepler’s clocks and voltages will automatically adjust on the fly, depending on the load required (or not). The card will also downclock if the horsepower isn’t needed, while traditional cards are stuck at full throttle. So a Kepler card is drawing less power, while running cooler and quieter, but can jump right back up to peak clocks in a fraction of a second if necessary. Now that’s innovation, folks.
So overclocking is different now. In MSI Afterburner, we increased the GPU Clock Offset (ie-the Boost Potential). Remember though, this is a target speed, not a guarantee. Then we also increased the Power Target slightly, to allow the card to increase the voltage automatically and account for the higher clocks.
Now that we have a better understanding of how overclocking works with Kepler, below are the results of our efforts. We finished with a Base Clock of 1128MHz, 1705MHz Memory, and 1206MHz Boost Clock. Keep in mind this is on top of what ZOTAC has already done with the factory overclock on the card. Needless to say, there’s plenty left in the tank, and the GTX 660 Ti is just another example of the great work done by Nvidia on Kepler, evident here with the AMP! Edition card by ZOTAC.
The Boost Clock was a pleasant surprise, but the overall final overclock wasn’t quite as high as we’ve achieved on other GTX 660 Ti cards. This result was also very borderline stable, good enough to finish the benchmark, but we did have to back things down slightly on the memory, as we experienced a bit of artifacting. Overclocking results certainly vary, but we’d recommend keeping the clocks a bit more moderate here, as there isn’t any sort of bulletproof power design or beefed up components designed to withstand long-term high stress situations.