New Geekbench scores of the forthcoming iPhone 4S show that its custom-built A5 CPU is clocked at 800MHz, while the dual-core processor gives it a 73 percent performance boost than the iPhone 4.

The new figures from AnandTech show the iPhone 4S with an overall Geekbench score of 623, easily besting the 800MHz A4 CPU found in the iPhone 4. The iPhone 4S processor is clocked slower than the 1GHz A5 CPu found in the iPad 2, which earned a score of 751.

And in terms of its graphics processing capabilities, the iPhone 4S lived up to claims of being seven times faster than the iPhone 4. In one test, the iPhone 4S earned a score of 73.1 while the iPhone 4 took 11.2, and in another the iPhone 4S clocked a score of 122.7, compared to 15.3 for the iPhone 4.

GPU scores for the iPhone 4S, like the overall CPU score, were slightly slower than the iPad 2. But they also easily bested the competition, including the Samsung Galaxy S II, Samsung Infuse 4G, and Motorola Droid Bionic, all of which feature processors with higher clock speeds.

The site noted that while lowering the clock speed of the A5 from 1GHz in the iPad 2 to 800MHz in the iPhone 4S results in a "marginal loss" in performance, but "yields a greater-than-linear decrease in power consumption," offering the handset even greater battery life.

"At a lower operating frequency than its Android competitors, Apple does have to exploit its strengths in software to avoid any tangible performance penalties," authors Anand Lai Shimpi and Brian Klug wrote. "Apple has traditionally done this very well in the past, so I don't expect the loss of frequency to be a huge deal to the few who cross-shop iOS and Android."