Yeah my Sabrent 5Gb USB adapters top out at approx 3.5, whether via my 10Gb switch (connected @5Gb) or point-to-point (USB adapter-USB adapter on different box). It's still around 750-1000mb higher than 2.5Gb, but you could argue that's not worth 3x the price of a 2.5Gb USB adapter. I think it is. They definitely get warm though. They've been ..... mostly reliable. I do, on a particular PC, have it basically strangle the bus and kill the box eventually, but I can also copy a few TB over the link before it happens so .. meh. It's just a download PC so a reboot isn't a big deal. The ones connected to a pair of Synologys have worked pretty well though after I compiled my own driver for them.