After iPhone 4S went into the hands of reviewers, one thing that made headlines was that the dual core A5 processor on iPhone 4S has slower clock speed at 800MHz than A5 processor on iPad 2 running at 1GHz. This news raised a big question, will the iPhone 4S be able to match the performance offered by new Android phones like Samsung Galaxy S II that features dual core processor running at 1.5GHz?

As you can see in the graph above, GeekBench benchmarking results showed that the 800MHz processor on iPhone 4S was slower than 1GHz A5 processor on iPad 2. Overall, the iPhone 4S score was about 20% lower than iPad 2.

However, when compared to other smartphones on the market the story is totally different, even though the iPhone 4S has a processor running at a lower clock speed than other top-of-the-line Android smartphones.

In browser benchmarking tests done by Anandtech, iPhone 4S came on top. It was about 40% faster in SunSpider JavaScript Benchmark than second placed iPhone 4 and third placed Samsung Galaxy S II. And in Rightware BrowserMark test iPhone 4S was 60% faster than Galaxy S II.

When it came to graphics performance iPhone 4S again topped every other smartphone including Galaxy S II, Infuse 4G, Motorola Bionic, LG Optimus 3D and Nexus S. In both GLBenchmark Egypt and GLBenchmark Pro, iPhone 4S was over 60% faster than every other smartphone.

In a side-by-side browser speed comparison test done SlashGear, in which they compared the new iPhone 4S to the new Samsung Galaxy S II running on 1.5GHz Qualcomm processor. The iPhone 4S with A5 processor came on top in most website load tests even against the Qualcomm processor, which claims to be running almost twice as fast as the reported clock speed of iPhone 4S chip (800MHz). Check out the video posted by SlashGear below.

Earlier this year, when Apple launched the iPad 2 with new dual core A5 processor we saw that not only was the A5 processor 2-5x faster than any other ARM based processor on the market, but it was more power efficient also. And it looks like even after Apple lowered the clock speed of A5 chip to fit the processor in iPhone 4S no one is able to match the performance offered by Apple’s A5 chip.