Mike Ybarra (ex-VP of Xbox, now at Blizzard) confirms through a Youtube live chat reply (lol) that I/O speeds on PS5 are better than anything seen on PC, also implying XSX could be similar.
Note that in the first part of the message he is referring to XSX, as the people in the video where talking about XSX(not Sony/PS5) and how would it compare to high-end gaming PCs of today. Then in the second part he states that what Sony has shown is in fact (better than the PC has ever seen).
The video in question:
https://www.youtube.com/watch?v=WcZtZaZmGwM
You can see him in chat starting from
1:01:41, although he doesn't say anything really noteworthy. He makes a few remarks like 8K being far away, how you can't just directly compare console integrated hardware to PC hardware, and also complaining about people focusing too much on
XBox Series X as a name, instead of focusing in other more relevant core values.
The bit about I/O comes at
1:29:30 and the host notices it and replies at
1:30:39.
What's interesting to me is that while he confirms Sony's claims, he doesn't seem so certain about XSX matching those specs, he just expects it. This is strange because with him being now at Blizzard, you would think he has access to both devkits.
(This comes from another thread but the mods closed it, asking to keep this kind of crazy talk contained in this thread.)