The Samsung Galaxy S II was one of the most powerful phones of its time, but in tech things move quickly. Quad-core phones are already on their way to a store near you, so these two phones will have to be at the top of their game if they want to stay relevant.
Samsung's Galaxy S II and the ICS-running Galaxy Nexus are the only ones to finish the CPU-intensive test BenchmarkPi in under 500ms. The Xperia S on the other hand matches the HTC Sensation XE and the Motorola RAZR XT910.
Linpack tells a different story though - here the Galaxy S II and the Xperia S are equally matched and well ahead of the competition (even the Galaxy Nexus).
The Xperia S and Sensation XE both have two Scorpion cores running at 1.5GHz, but their results are very different. The rest of the CPUs here have two Cortex-A9 cores (1GHz for Galaxy R, 1.2GHz for the rest) and they get quite different results too.
For graphics performance, the Sony Xperia S and the Samsung Galaxy Nexus are at a disadvantage performance-wise with their 720p screens, but the image quality is better. Still, the Xperia S and its Adreno 220 manage the very playable 37.5fps, second only to the Galaxy S II, which has only about 40% of the total pixels as the Xperia and manages 46.2fps.
Pretty much the same goes for the BrowserMark test, which also gauges the browser's HTML capabilities. The HTC Sensation XE jumps ahead and is a very close third, behind the Sony Xperia S. And both are well behind the ICS-running Galaxy Nexus.
We ran our battery tests on the Sony Xperia S and it's ready to go head to head with the Samsung Galaxy S.
The Sony Xperia S gives you about 7 hours and 41 minutes of talk time and coincidentally that's exactly as long as the iPhone 4S. The Samsung Galaxy S managed to endure nearly an hour more.
Then there's web browsing - the Xperia S takes this round by lasting an hour longer than the Galaxy S II but it's still about a couple of hours shy of the leaders in this category (which have smaller, lower-res screens though).
The mostly white pages hurt the Galaxy S II's AMOLED screen, but movies are another matter - it lasts 8 full hours of movie watching, while the Xperia S manages just 6 hours and 25 minutes.