Oh well, I might as well stop lurking for one post so that this profoundly absurd discussion stops going entirely in the wrong direction
Here are, nearly certainly, the major changes:
- Infineon 65nm X-Gold 616 Baseband (integrated baseband PMU) with 130nm Infineon UE RF (many fewer external components) linked over DigRF 3G.
- No Baseband SRAM, uses the very rare Shared-DRAM interface (see X-Gold 616 datasheet) that allows the Baseband to share memory even standard LPDDR1. Complicates memory controller scheduling on the app processor quite a bit, but obviously saves space/cost.
- Infineon 65nm XPOSYS GPS chip instead of Infineon 130nm Hammerhead I/II (thse are actually the same silicon). Very small chance they went with the CSR SiRFStarIV instead.
- The Bluetooth/WiFi module is still from Taiwan-based USI but it's a new version, not a rectangle like the iPad. Presumably still using the BCM4329 though, but impossible to be certain.
- Unlike the iPad where the screen was too big for it, they are nearly certainly using the more space-efficient touchscreen solution from the 3GS.
The A4 is on 45nm, unlike the 3GS's SoC but uses the same CPU and GPU. That means it's probably *cheaper* (although there's the extra cost of the 64-bit memory bus) and there's absolutely no reason to speculate on what other processor Apple might be using. And as seems very clear here, footprint of modern phones even with discrete app processors can be very very small.
As silent_guy said, there's not much benefit from integration there. It still makes a lot of sense for Qualcomm or ST-Ericsson though, in which case it should be seen as a partial lock-in strategy: "if you want our application processor, you need to use our baseband", and pricing-wise it's probably fair to see it as mostly a mere bundling advantage going forward (there is a cost benefit, but it's not big).
More interesting, of course, is what Apple plans to do with the VXD375 in the A4 - presumably they couldn't do HD video on the 3GS because they lacked memory bandwidth but that's solved now. I do suspect a bit that VXD375 might be a 720p-only variant of the VXD370, in which case that's what we'll get like on the iPad. We'll see.
