Overclocking is not an exact science. When it comes to overclocking headroom, every GPU is different. And just because your friend's GTX 480 hit 900MHz doesn't mean that yours will, even using the same settings and hardware. Many factors can influence what a video card is capable of, starting with the unique capability of each GPU. These factors may also include complementary components within the system, but we find the primary influence is the type of cooling used on the graphics card.
To overclock the Hydro Copper FTW, we used two excellent utilities from EVGA. Precision is a GPU overclocking and real-time monitoring utility that allows fine tuning of the core, shader, and memory frequency. It also provides independent or synchronous fan controls for multi-GPU systems. You can save up to 10 profiles with the ability to assign hotkeys for in-game access. We also used EVGA E-LEET tuning utility which allows GTX 480 voltage adjustments, as well as PWM frequency modification.
We found stability at an impressive 944MHz core and 1125MHz memory frequency with voltage set at 1.175V. That's a 26% GPU overclock over the rated speed of the Hydro Copper FTW video card, and a 35% increase over the reference design speed clock These settings allowed us to game and run benchmarks with no issues. E-LEET offered higher levels of voltage settings, and although our temps remained in check, we refrained from pushing our luck further.