3DMark
3DMark is the latest version of this hugely-popular synthetic benchmark. Making use of DX11 features such as tessellation, compute shaders and multi-threading, it provides modern-day results and is available as a free download.
The amount of factory overclock is reflected perfectly in the synthetic 3DMark analysis. The reference card is impressive as it is, but Gigabyte's WindForce 3X is up to five per cent faster, and EVGA's massively-overclocked variant is faster still.