@matigo It arrived today and I've been testing various cables. Two surprised me, as far as I was aware from the website where they'd been purchase, they were USB 2.0 speed cables, on account of their length of 2.6 metres. Turns out they are USB 4 cables, with power handling up to 240 watts and up to 48 volts. I tried three different Thunderbolt 3 cables, only one was capable of 40 GBps, the other two were 20 GBps only.