In the PS5 case, the goal was for the decompressors to never be the bottleneck in real workloads, so they're dialed in to be fast enough to keep up with the SSD at all times, with a decent safety margin. That's all there is to it.
Along the same lines,
2 helper processors in an IO block that has both a full Flash controller and the decompression/memory mapping/etc. units is not by itself remarkable. Every SSD controller has one. That's what processes the SATA/NVMe commands, does the wear leveling, bad block remapping and so forth. The special part is not that these processors exist, but rather that they run custom firmware that implements a protocol and feature set quite different from what you would get in an off-the-shelf SSD.
September 30, 2020 at 7:56 PM