ere's benchmarking test between the Galaxy S3 GT-i9300 with Exynos 1.4Ghz Quad-core processor vs. Galaxy S3 T999 Qualcomm S4 1.5Ghz Dual-core processor.
As expected, Qualcomm S4 gives near identical results to AT&T One X (which has Qualcomm S4) also but extra gig of memory seems to help just a tad, not much though.
Sprint/AT&T/Verizon Galaxy S3 results should be near identical to the T999 also as they share the identical hardware specs.
But does that mean U.S. versions of Galaxy S3 are going to be slower than international versions? No, don't get the benchmarks upset you in any ways, these are purely "benchmarks" and only show what the hardware is capable of. The real comparison comes with real-life testing in real situations and based in my opinion, this isn't going to affect most users as both processors are plenty-capable of yesteryear's smartphones.