PS4 & AMD Kaveri APU both feature the Onion + HSA memory Bus (PlayStation 4 )

AMD new Kaveri APU features the same Onion+ Bus found in the PlayStation 4. 

So it's pretty safe to say PlayStation 4 APU is Heterogeneous System Architecture.

PS4 Liverpool APU Memory Bus

Kaveri HSA Architecture 

GDDR5 is shown in the Memory Hierarchy slide.