The AMD Jaguar platform used a form of PCIe (a bus standard) in its internal communications, particularly between the CPU and GPU components of their APUs, with which the PS4 (and XBone) is equipped - staying with x86, Intel does something similar, centralising a lot of functions on the CPU die. Furthermore, the PS4 uses a bespoke "HSA friendly" memory setup for the CPU and GPU, which affects data flow as well, and is probably one of the more distinct aspects of the PS4's hardware, as compared with the XBox One and even AMD's own PC analogues to-date. However, sticking with AMD would mean little real change to this approach, especially given the attractiveness of putting all the big bits of silicon in one place, and AMD are still making entry level and "mobile" spec APUs. Swapping to Intel won't be a massive difference either, although they don't have the same integrated graphics clout. As mentioned, since it's all x86, this route would mean PS4 emulation should be relatively easy. Whilst a completely different bus architecture could imply a complete change in hardware vendor, they are unlikely to go for anything truly exotic (like the PS2 and PS3 were) now they've settled into the x86 safespace - this allows games to more easily be made cross-platform. So this reference to a "legacy bus model" is indeed just as likely to be a hint that PS2 and PS3 games will finally be backward compatible, particularly since the work for PS2 games is half-done already. But: a real curveball would be for Sony and / or Microsoft to align their new console(s) with mobile development and use a souped up mobile chipset... For example, ARM architecture chips are making headway in power-conscious areas, e.g. enterprise / servers, and may even appear for laptops etc. These have also tended to be paired up with some serious graphics heft on the same silicon, all with very low power draw. Mobile phone usage in particular requires the use of innovative hybrid schemes to balance load across a few different types of "cores" to do different jobs at different times - in the context of a games console, such a heterogeneous (HSA!) design could prove useful for streaming, browsing, home theatre etc. Unfortunately, going that route could make PS4 game emulation actually very tricky without some serious horsepower, but still leaves PS2 and PS3 on the table IMO.