According to reports, the PS4 will incorporate hUMA, which stands for Heterogeneous Uniform Memory Access, into the system, and the Xbox One will not. According to AMD’s–the company behind hUMA–senior product marketing manager, this will give the PS4 a significant edge over the Xbox One.
If you’re unsure as to what it is exactly hUMA does, don’t worry, you’re not alone. Sources over at PSU found a good explanation:
“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.”
Source: Heise
