Sorry for this kinda gamerbrained question.

The Xbox 360, Playstation 4, Xbox One, honestly most consoles after the Playstation and Saturn have shared memory pools. It allows flexibility in how much memory and VRAM developers want to assign, right? Why does the PS3 not have a shared 512MB pool of GDDR3? It caused all kinds of problems, most notably with Bethesda games.

Is it the Cell Broadband Engine needing the specialty XDR memory? Is it an artifact of the Nvidia RSX graphics chip being added late in development? Looking back I a)most wonder if the split memory was more of a problem than the Cell tbh.

  • ashinadash [she/her]
    ·
    2 months ago

    You can tell me abt the memory map if u desire ✨ but uh

    Because of the VERY slow Cell Read speed from the 256MB GDDR3 memory, it is more efficient for the Cell to work in XDR and then have the RSX pull data from XDR and write to GDDR3 for output to the HDMI display.

    There are also bandwidth differences up to 10gb/s between the different busses. Add the high latency of GDDR3 compared to the XDR RAM, and the fact that the Cell doesn't seem to have access to the GDDR3... The RSX having to request access from Cell puts me in mind of Pentium Ds and other really early dual core CPUs, lol.

    But this basically all means that using the two pools as a single continuous memory chunk would be impossible, right? The Xbox 360 sounds much more normal to me, I would bet without knowing that the PS4 and XBO also have large caches to offset GDDR latency. The OG Xbox has a large CPU cache as well =) which seems much funnier than this weird split ram shit.