Craig, where did it say that they're going from 4 CPU cores to 2?
They didn't. I don't know where the rumor came from but it's not going to happen. There's no way OMAP5 will be ready in 2011. It's strictly a 28nm part. You'll be lucky to see it in a product in 2012. Besides, OMAP chips are relatively expensive, and Sony isn't going to use an off-the-shelf SoC when it can license IP directly. It's also known that IMG has made modifications to SGX543MP4 on Sony's behest (they've said so themselves), this wouldn't be consistent with OMAP5. It's also known that NGP is dedicating one of its four cores for OS resources and obviously quad-core has been one of the major selling points.. right now we don't even know if OMAP5 will be offered with MP4 GPU (at least not at first).
(this is kind of why Tweet's annoy me.. they barely give you room to even try to substantiate a claim, lending themselves to ridiculous rumors)