UPDATE - AMD has contacted PSU to retract the statement made by a representative at Gamescom regarding huMA. Check out this article for more details.
PlayStation 4 incorporates huMA [Heterogeneous Uniform Memory Access] from AMD, which apparently gives Sony’s hardware a significant advantage over Xbox One.
According to a German I.T magazine, translated here, it means that the 3D performance of the PS4 is way ahead of Xbox One. The news was sourced from AMD's Senior Product Marketing Manager Marc Diana.
We’re not particularly technical at PSU but we know a guy who is...
Explaining what huMA means for PS4, DoesUS says:
"On a classical system you have a RAM pool and a VRAM pool that are physically separated. Copying data from one pool to the other creates latency. The GPU is very good ad hiding latency. What it needs most is high bandwidth. The CPU on the other hand is extremely sensitive to latency. The CPU needs extremely low latency to work efficiently. Copying data from the RAM (CPU) to the VRAM (GPU) creates latency, but that's okay for the GPU. Copying data from RAM (CPU) to VRAM (GPU) and back to the RAM (CPU) creates even more latency. It's too much for the CPU. The copying alone takes longer than the computation wich makes this roundtrip highly ineffective.
Xbox360 and older APUs have a unified RAM. This means that the RAM is no longer physically separated, but even though it's the same RAM chips, the system still distinct between memory partition for the different processors. You still need to copy the data between CPU partition and GPU partition, but this will be much more efficient than copying it between physically separated pools. But it's still too much latency for a CPU, GPU, CPU roundtrip.
PS4 will have hUMA wich means that you no longer need a distinction between CPU partition and GPU partition. Both processors can use the same pieces of data at the same time. You don't need to copy stuff and this allows for completely new algorithms that utilize CPU and GPU at the same time. This is interesting since a GPU is very strong, but extremely dumb. A CPU is extremely smart, but very weak. Since you can utilize both processors at the same time for a single task you have a system that is extremely smart and extremely strong at the same time.
It will allow for an extreme boost for many, many algorithms and parts of algorithms. On top of that it will allow for completely new classes of algorithms. This is a game changer.”
We guess the proof will be in the pudding when we actually get to spend time with these consoles, and PlayStation 4 will have the first bite of the cherry when it launches in November.