Don't let the number of cores fool you. The S4 Snapdragon (Krait) is VERY powerful. It is on a much smaller (28nm versus 40nm) die than Tegra 3 and is both cooler and more power efficient. Also it has the LTE radio on that same 28nm die so we finally get LTE speeds without the monster power consumption. Plus when it ships with the Adreno 300 (which I think the GS3 does) the GPU power will be in the same class as an XBOX 360 or PS3.
Anandtech did a deep dive into Krait which was interesting:
http://www.anandtech.com/show/5559/...mance-preview-msm8960-adreno-225-benchmarks/1
http://www.anandtech.com/show/5563/qualcomms-snapdragon-s4-krait-vs-nvidias-tegra-3/1
In a phone, Krait is proving faster and less power hungry than Tegra 3 (which surprised many).
The "faster" statement is a bit misleading. They show that the Snapdragon performs faster than the Tegra 3 in single or lightly threaded apps. One-to-one core comparison between the two may prove that Snapdragon has some advantage but the number of cores *is* an important factor in this case because the individual cores in each processor are not all that far apart in real world performance, which is one reason why the Tegra 3 will ultimately have the performance advantage due to the sheer number of cores.
I've read article after article written by tech heads who are trying to sugar coat the disadvantage of having an inferior processor in the North American model. In the end, it's really nothing more than settling, accepting and making the most of the garbage we're being served so Samsung could meet deployment deadlines before the S3 becomes obsolete in 3 months. The choice to use Snapdragon in North America is, as you pointed out, because of the LTE radio. In Korea, however, an LTE model is being released with the Tegra 3 processor and I'm very interested to see how that will go.
In our current reality, having the LTE on the same die isn't going to bring us Earth-shattering speed differences. It'll be much like HSPA+ vs LTE, where the speed advantage, for now, is negligible at best in real world applications.
What really drives me nuts, though, is how the American wireless carriers fragment the hardware market with firmware crippled features and frequency bands. Why they can't just be like the rest of the world and allow phones to work across networks is beyond me. Especially now, when most phones are built with both CDMA and GSM (all bands) radios in the same unit, it's just frustrating.