FM57:

Could we imagine this support as a substitute to traditionnal SSD ? Smaller, very fast, reliable (?)

I doubt it, the tech would fall back to early SSD development where there have been no write caches. In theory, they could do a partial SLC cache and or/a system buffer cache to divert it (thus a small portion of your system memory as cache), but other than that I think small files write issues would be a hindrance for your OS.

Impressive they managed to retain backward compatibility with this. I was about to get REAL pessimistic, but it looks like the SD Association handled this pretty well. The only thing I don't especially understand is how exactly this is supposed to yield any performance enhancement? Flash memory in and of itself isn't that fast, but SSDs have great performance because they have controllers with caches that can juggle data between multiple memory chips simultaneously. So, how exactly do you accomplish that in a microSD card? Existing cards can't even saturate USB 3.0 bandwidth.

I don't like how the cards fallback to such old standards if both host and card don't MicroSD Express. That sucks because the cards would be abel to fully saturate UHS-II & UHS-III but instead they're locked to UHS-I (104). https://www.overclock3d.net/gfx/articles/2018/07/03045152122l.png