We spent a little time overclocking the GeForce GTX Titan to see what kind of additional frequency headroom it had left under its hood. For these tests, we used the latest edition of EVGA's Precision X GPU tweaking utility, which is designed to work with Titan.
Overclocking a Kepler-based GeForce GTX series graphics card requires a bit more tweaking then previous-gen products, due to all of the new options available and the complexities associated with GPU Boost. Sometimes, you’ll find that increasing a particular voltage or frequency may appear to function properly, when in fact performance decreases due to errors or throttling. You may also find that the actual GPU Boost clock may travel above or below the designated offset value when the power and/or temperature targets are also increased.
We did a few things when experimenting with overclocked speeds on Titan. First we tried the most basic option available--we simply changed the temperature target from the default 80'C and increased it to 90'C to see what kind of impact it would have on performance. Then, to push things much further, we increased the power and temperature targets to 105% and 92'C, respectively, and also increased the GPU and Memory clock offsets and ran a few tests.
Interestingly enough, increasing the temperature target to 90'C resulted in a small increase in performance, not only because the GPU was able to run at higher boost frequencies for longer periods, but the boost frequency actually increased as well. Although the default GPU boost clock on Titan is 876MHz, we observed frequencies as high as 993MHz. For our more aggressive overclocking tests, we saw a much higher GPU boost frequency of almost 1.1GHz, and when coupled with higher memory clocks, the performance increases were significant. Hitman in particular showed a 12% increase in performance. Keep in mind, these clocks were possible without manually tweaking the Titan's voltages. With further experimentation, we're certain the GeForce GTX Titan can hit even higher clocks than what we've shown here.
The moral of the story: Even with 7.1B transistors under the hood, the GeForce GTX Titan has plenty of frequency headroom left for overclockers.