>> Just this monday morning I've spent 20 minutes checking all the cables and why it doesn't work, until I rebooted the machine and then it suddenly worked.
Mnyeah. The fabled Mac-Windows convergence, as foretold in the days of yore. MS hardware gets sleek commercial blogposts from evangelists, like Macs; and Apple's OS needs to be rebooted every once in a while to work right, like Windows.
Given the recent updates in 10.13.x for external GPUs, it might not have been a reboot that fixed the problem, so much as a deferred update to a point-release that fixed a problem created in the previous point-release.
Mnyeah. The fabled Mac-Windows convergence, as foretold in the days of yore. MS hardware gets sleek commercial blogposts from evangelists, like Macs; and Apple's OS needs to be rebooted every once in a while to work right, like Windows.