Thursday, February 28th 2013

AMD Working On Stripped-Down PlayStation 4 SoC for PCs

Ahead of its unveiling last week, it was expected that Sony's PlayStation 4 console would be driven by little more than an AMD A-Series "Trinity" APU. It ended up being a lot more than that. The custom-design SoC that drives the next-generation console is a joint effort between AMD and Sony, which integrates an 8-core x86-64 CPU based on the company's new "Jaguar" micro-architecture; a GPU based on its Graphics CoreNext technology; a GDDR5 integrated memory controller, and certain enhancements by Sony. In an interview with The Inquirer, the company hinted that it's interested in porting the SoC over to the PC platform, minus Sony's share of the development.
PlayStation 4, although based on the x86 CPU machine-architecture, doesn't conform to any known PC specification. It uses 8 GB of GDDR5 memory as both system and graphics memory, several of its interfaces are out of specs of anything that can be implemented on a PC motherboard. Therefore, its SoC can't simply be soldered onto a PC motherboard. AMD would have to first strip the SoC of Sony's share of the development (or risk having to license it).

Next up, it would have to strip the chip of its most interesting component, the unified GDDR5 IMC. JEDEC does not have a GDDR5 DIMM specification, nor would motherboard makers be interested in hard-wiring expensive GDDR5 memory chips on to their motherboards and render the memory subsystem non-expandable. The PlayStation 4 SoC uses a 256-bit wide GDDR5 memory interface, with a stellar memory bandwidth of 176 GB/s. That's over six times the memory bandwidth of an Intel Core i7 "Ivy Bridge" machine running dual-channel DDR3-1600 MHz. A fallback to DDR3 could hence greatly cripple the SoC. It would be extremely interesting to see how AMD handles the checks-and-balances needed to bring the SoC over to the PC.
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