I have Linux Mint Cinnamon installed on a flash drive, and even on USB 2.0 it’s pretty fast. The problem rather has been random access speed, not the transfer speed. I tried 3 unbranded flash drives from AliExpress and a Panasonic USB 3.0 flashdrive, and all of those were crap. The only one good for this has been SanDisk CruzerBlade, both USB2 and USB3 versions.