Power, Heat, And Efficiency
While our former build drew peak graphics power using FurMark, today’s build requires 3DMark to achieve a similar load. This is because Nvidia built in circuitry to its card that intentionally throttles back under extreme duress like FurMark forces. The company (along with AMD) considers this to be an unrealistic "power bug" that could potentially damage a card, but simultaneously prevents the company from clocking its chips as high as possible. Working around the loads applied by FurMark facilitates greater performance in real-world titles.
The GeForce GTX 580 is a larger and higher-performance graphics card than the previous build’s Radeon HD 6970, even in these SLI versus CrossFire comparisons.
Increased fan speed keeps the current overclocked machine’s GPUs cool, though the same can’t be said for the previous overclock.
More graphics power helps the new system keep its lead against the previous build, even though its overclock was unsatisfactory.
A moderate performance boost paired with a minimal increase in power consumption aids the new system as it approaches the previous build’s efficiency. It doesn't quite catch up, though.