As always, we start with 3DMark 11, a synthetic benchmark designed to test a GPU's performance at various aspects of DirectX 11 such as tessellation and DirectCompute. The Gigabyte GTX 780 showed a pretty decent performance increase here, of about 5-6%, leaving it just 4% short of the GTX Titan's scores.
For an idea of in-game performance, we chose Crysis 3, the toughest game in our benchmark set due to its extreme amounts of tessellation, per-pixel per-object motion blur, Bokeh Depth of Field, displacement mapping, particle and volumetric lighting and fog shadows.
The Gigabyte GTX 780 was very impressive, showing a much higher performance gain here, scoring about 10-15% better across all settings and resolutions.
As with the reference GTX 780, overclocking on the Gigabyte GTX 780 was fairly easy and we were able to raise core clock speeds to 1055MHZ, slightly less than the reference card. Compared to the reference card, we suffered no performance degradation when raising memory clock speeds, and settled on a stable memory clock of 6600MHz DDR. This is probably the result of the better cooling system that allowed the card to perform better and the results do show.
For our efforts, we were able to squeeze an extra 15% performance out of the card, which put it just 2.5% shy of our maximum overclocked GTX Titan - Impressive!