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Why does the Playstation 3 have split memory pools?
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I was writing something much longer but I started actually reading about the PS3's memory map and uhh
The memory pools aren't really split* orrr... I guess it depends what you mean by "split". The RSX can actually access the Cell's XDR memory, it's just somewhat slower because the RSX isn't directly connected to the XDR memory bus so it has to ask the Cell BE to make accesses. For comparison, it seems the Xbox 360's main memory is connected to the GPU which results in longer latencies for the CPU to access memory but apparently Microsoft partially mitigated this by the addition of more cache memory for the CPU.
*https://www.psdevwiki.com/ps3/RSX (scroll to: "RSX Memorymap")
sony nooooooooo bro this sounds soooooooooo annoying!!!
You can tell me abt the memory map if u desire ✨ but uh
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.