(Response and reply happened while writing this. Looks like some mild ninjaing going on.)USB 1,2 (Type A)
USB 3 (Type A)
Examine the respective socket/plug for signs of the extra five connectors. May need favorable illumination/line-of-sight, but the pale blue colour of the plastic tab is the industry-standard shortcut indicator that it (should be!) USB3, or "SS" (superspeed) written alongside the USB 'trident' sigil printed, embossed or in relief around the port/connector housing.
I may be just unaware of it, but SFAIK there is
no intrinsic reason for USB3 hardware (either host or peripheral) being unable to slob it with a non-3 (peripheral or host) complimentary connection. The USB 3.0 spec requires that devices be fully backwards compatible with USB 2.0 devices, and if it's not then it's not spec-worthy and could be deficient in other ways.
The top-rate of 'superspeed' won't be available, so it could not work with high-demand data transfer. But I'd expect that only to slow drive access (and neuter the better negotiatable framerates/resolutions of Ultra-HD webcams, maybe) not to not work at all. 'For reasons'. That sounds like a fudge like "My website isn't gonna bother to display for you, 'cos your browser is apparently, like,
soooo last year, and I can't be bothered to maintain the less fancy version without all the latest bandwidth-hogging bells'n'whistles!".
I know you suggest you got the (alleged USB3) original stick supplied alongside the main hardware, but can you check that the supplier has remembered to properly 'bootify' the thong, and not just copy it across
without bootability set? It could be a honest error. Or the "slow down to a crawl" might suggest a 'disk error' on the stick encountered
while bootstrapping. Needs several more stages of investigation to rule in/out various possibilities.