From the get-go, we have a problem: The APU in the PS4 is unique. It pairs an 8-core Jaguar CPU with, essentially, the Radeon HD 7850.
The best AMD APU currently on the market (the Richland A10-6800K) has about one third of the processing power of the PS4′s GPU. There are no 8-core Jaguar parts on the market — only the quad-core Kabini A6-5200, which is paired with an even weaker GPU than the A10. Kaveri, when it
comes to market in January 2014, will be a closer match — but
the PS4 will still have around twice the graphics grunt. In short, we’re forced to use a CPU and discrete GPU. It just got a lot harder to hit our $400 target.
The other big problem is the 8GB of GDDR5 RAM, which has an utterly insane peak bandwidth of 176 gigabytes per second.
There is no way to build a PC with such a configuration. In the PS4, the RAM is used by both the CPU and GPU in a
HSA 2.0 configuration, providing a sizable speed boost –
an option that isn’t available to the PC world until Kaveri launches. It’s important to note that even if we could slot some GDDR5 RAM into a PC motherboard, it would probably be much more expensive than conventional DDR3.