Toid wrote:

My old laptop has USB2 ports.
It also has MM slots which are now empty.

Is there a MM card that adapts to USB3 ?

Most important, does using such a MM card get the data transfer speed up
to or near USB3 speed ?

Since you don't mention a USB 3 port then you don't have USB3 support.
Pushing a faster MMC (not MM) card into the slot is not going to make
the slot faster. Need a new laptop. Won't help speed up an MMC card,
though; see:

https://en.wikipedia.org/wiki/Compar...hnical_details

MMC: max read speed = 2 MB/s (16 Mbps), max write speed = 2 MB/s (16
Mbps)
USB 2.x: max speed = 60 MB/s (480 Mbps)

The USB2 controller to which the card slot is connected is far faster
than any MMC card you can slide into the slot. Not until you get a
flash card that exceeds 60 MB/s (480 Mbps) would the slot support a card
capable of USB3 speeds, and no MMC card is that fast (the eMMC is BGA
soldered, so it is not user-removable media).