Definitely seems to be limited by power restraints...Highest GPU Overclock Only
This is the highest obtainable GPU-only overclock we could manage. We are only overclocking the GPU while memory is left at default.
With the fan at 100% and the Power Target at 120% we managed a top GPU offset of +230. We found that at +250 the video card locked up in games. At +230 it did not lock up. What does that result in? In the graph above you can see that the overclocked GPU clock speed starts off at a high 2113MHz, but then quickly declines to around 2080MHz. Finally after some time playing it settles to an average of 2062MHz for the remainder of gaming.
This is why it is important to test long sessions of gaming to see the final resting place for the clock speed. Keep in mind our card is on an open bench with an ambient temperature of 72F, so this is best case scenario temperature-wise.
The red line below shows you the default clock speed for comparison. The lowest clock speed of the overclock spiked down to 1873MHz very briefly, but otherwise the average new clock speed is 2062MHz versus 1770MHz average clock speed at default operation.
That is a 16% increase in clock speed while gaming. Keep in mind this is all with a 100% fan speed and Power Target at 120%. However, this is with NO voltage changes at all. We are letting GPU Boost 3.0 handle voltage, which seems to work out very well.
Temperatures hit a maximum of 62c with this overclock and 100% fan speed.