Despite its extra 300MHz per core, the T-Mobile version of the Samsung Galaxy S II is no faster than its counterparts on other carriers, according to our tests. The phone neither feels nor benchmarks differently than its 1.2GHz dual-core brethren, so it likely won’t be worth it to switch carriers just for the internal hardware.
The T-Mobile Galaxy S II was confirmed to have a 1.5GHz dual-core processor, making its later launch a little sweeter. We’d hoped that would mean even more blistering performance than the Sprint Galaxy S II that already impressed us, but that was not the case. Of course, the processors are of different makes, which accounts for the different somewhat (T-Mobile's is a Qualcomm, Sprint's is Samsung's own Exynos).
The T-Mobile Galaxy S II's Linpack scores, multi-threaded, left, and single-threaded
The T-Mobile Galaxy S II's Quadrant Standard score
The T-Mobile Galaxy S II sticks to a score of around 3600 in Quadrant tests—much better than most other phones available right now, but no better than the Sprint version we tested. And the T-Mobile Galaxy S II’s Linpack benchmarks were less impressive, with 47.606 MFLOPS in single-threaded processes and 72.953 multithreaded, compared to the Sprint version’s 53.877/93.392. In regular use, it feels no faster.
The reception wasn’t all that great, either: on three of four bars on T-Mobile’s 4G network, we clocked download speeds at 2.7 Mbps and upload at 344Kbps (though we're not in range of the 42Mbps connection speeds). T-Mobile is cheaper than the other carriers, and different networks serve different people better in different places, but that doesn't scream "4G" to us.
This doesn’t make the T-Mobile Galaxy S II a bad phone—the phone is, after all, basically the same as its Sprint cousin (with a couple of cosmetic differences), and the entire family of Galaxy S II’s are still arguably the best Android phones you can buy. Just don’t go switching carriers based on that processor clock.