I think it's pretty clear MS's solution is definitely "punching above its weight", as the saying tends to go. I mean, there was a lot of evidence to suggest this would be the case beyond the paper specs, but it's not like MS's been 100% transparent on info regarding the SSD I/O either. For example there wasn't as much on it as most would've liked at Hot Chips.
Both of these systems are solving a big problem from last-gen though when it comes to load times; I don't think we'll get a super-strong impression on what the SSD I/O for both systems can do until we start seeing games natively developed for the consoles leveraging that hardware. On that note, PS5 kind of has an advantage because of R&C, Demon's Souls Remake etc. coming out sooner rather than later (or in some cases, right at launch).
However, I think this is all also validation of some stuff a few of us were saying months ago: you're
not going to get games that are possible on one system suddenly impossible on the other due to what paper specs relating to SSD I/O say, because in practice both system's solutions will be very performant with each other when all of the aspects of their I/O design are taken into account.
Great news for anyone getting either (or both) systems, I say
They're partly right about that, because data requests still need to ultimately be handled through the CPU. Some folks on B3D explained this better than I could, but essentially things don't just "end" at the SSD; the CPU still needs to do a bit of work.
However I also think part of it is because MS's solution is probably more elaborate than people give them credit for. I know it's easy to assume how it plays out looking at paper specs but given what we're starting to see in practice, it's apparent both Sony
and Microsoft did a lot of work to ensure their solutions hit optimal levels of performance.