Just like with the HTC One X, which had a quad core Tegra 3 version internationally, but a dual core Snapdragon S4 version in the US, because it was the only available chip with an integrated LTE modem: the Galaxy S3 came with an Exynos 4 Quad chip for all non-LTE markets, and a Snapdragon S4 for the LTE ones, including the US market.
So until now, if you were an American citizen, you couldn't even choose the quad core version if you wanted, for the GSM networks. But that may be about to change soon, as Samsung is apparently going to launch an unlocked version of the Galaxy S3, the same i9300 model we saw on the international market, at certain retailers in the US.
The above leaked image shows us that this model will be coming to Best Buy and it will cost $800. That's quite pricey compared to an unlocked Galaxy Nexus that now goes for $350, but that's what you'll have to pay if you really want a quad core Galaxy S3.
The color is marked as “blue”, which most likely means it will be the same pebble-blue that was announced in the beginning, or it may feature a different kind of blue. We already know that there will be a “Garnet Red” exclusive model for AT&T, and rumors say that there may be more color options coming soon.
It's a little hard to tell the difference between the quad core 1.4 Ghz Cortex A9 CPU and the dual core and slightly higher clocked (1.5 Ghz) Snapdragon S4 that has a next-gen design. So you can't really compare them directly. The Snapdragon S4 will be better at single-threaded apps, and the Exynos 4 Quad at multi-threaded apps. Benchmark show them about equal most of the time, but in some of them they give the quad core chips higher score for having more cores. In the BrowserMark benchmark, the Exynos 4 Quad seems to beat everyone else handily!
We do know that the overclocked Mali 400 GPU inside the Exynos 4 Quad is superior to the Adreno 225 in the Snapdragon S4, and that's not very surprising considering the Adreno GPU's have always lagged behind the competition a bit. But hopefully that will change with the arrival of the Snapdragon S4 Pro and Adreno 320, although it's unlikely it will beat the upcoming Mali T604. For now, the overclocked Mali400 GPU remains the king in smartphone land.