I have the other USB3 port installed and tested in the RecRoom now. All fine.

I have the other USB3 port installed and tested in the RecRoom now. All fine.

A side benefit is that I found a spare 3m HDMI cable that had been misplaced. I swapped that into the Lounge PC (though it was a Herculean effort to plug it into the back of the TV). I'd also found a couple of plugs on the graphics card I'd installed on the RecRoom PC (in order to play Space Engineers) and it transpired that they were HDMI! That means I can now use the 4K monitor in the RecRoom properly! Win win today.
#USB3