Comment by fabiensanglard

4 years ago

Actually, I just noticed that 128/132 is the same fraction as 66/64 so both scheme has the same encoding efficiency. So USB-4 did no "revert in terms of efficiency.

Indeed, according to the wiki page the subtetly is:

> USB 3.1 and DisplayPort 2.0 use 128b/132b encoding, which is identical to 64b/66b, but duplicates each of the preamble bits to reduce the risk of undetected errors there.

I guess that was found not to matter so they went back to the more normal 64/66 in USB4? I'm really weak on the hardware stuff so I really have no idea.