GPU Boost caused a bit of a stir when it was first introduced because it did away with the traditional 'absolute' method of dictating MHz. Rather it worked by overclocking the card by different means. To achieve an overclock using GPU Boost, one increased the MHz and Voltage as per usual however the card would then 'Boost' when placed under load. So rather than having a fixed clockpseed, the GPU adjusts the clockspeed depending on load, ensuring the power is there when you need it rather than it being full on all of the time, thus saving power consumption and heat production by having the card overclock dynamically.
GPU Boost 2.0 is an evolution of this idea. The techs at NVIDIA have determined that GPU power was unnecessarily limiting performance when GPU temperatures was low. Instead of boosting GPU performance based on a power target, it is now based upon temperature with this temperature threshold being 80 degrees Celsius.
Because the boosting is now determined by temperature, noise levels are also reduced as NVIDIA claim the GTX cards deliver a better acoustic profile.
So to summarise, overclocking the card using GPU boost 2.0 means adjusting the temperature threshold, for example from 80c to 85c. The GPU clockspeed will then gradually increase until it reaches this new temperature and will be dynamically adjusted on-the-fly to stay within this threshold. Because of this it is much more difficult to claim one GPU is faster than another without having both working under precisely the same operating conditions.
It therefore should go without saying (but we will say it anyway) that the colder your card runs, the faster it should theoretically operate as a colder card allows overvolting and thus even higher clockspeeds.
GPU Boost 2.0 also features overvoltage control. NVIDIA make no bones that enabling this function will damage the long term operability of the graphics card and as with AMD's overdrive, you have to acknowledge this fact before you can unlock the cards voltage control. We applaud NVIDIA for this because they have acknowledged that enthusiasts, like us here at Vortez, like to push hardware to the max and without voltage control, the whole process becomes so much more uninteresting and much more difficult.
So, because GTX770's boost clock and voltage level are now tied to the GPUs temperature, the voltage can be dialled higher which in turn will allow the GPU to attain higher clockspeed values. Obviously, increasingly board voltage, as with most other products, will gradually degrade the GPU through electron migration causing a premature death of the GPU. Voltage support will be offered on a board partner by partner basis however, we would be extremely surprised if it wasn't enabled in every GTX770's VBIOS.
We will see how GPU Boost 2.0 performs in our overclocking section later in the review.