And my Surface Laptop 4 doesn’t even have Thunderbolt! But that’s a pathetic failure on Microsoft’s part.
Point being, Thunderbolt is amazing but in a very narrow usage corridor. When it works it’s amazing. When it doesn’t, jokes on you spending $90 on that single cable. I remember an LTT video on I think TB4, testing various combinations of devices and validating (in)compatibility, and spending a lot of time on Lenovo forums for support.
The Plugable brand manufacturer has a support page for one of their dock products that incorporates the same ASMedia chip that my CalDigit dock uses. Plugable links to updated drivers for Windows that it says improve reliability. However, that link is to an archive file hosted on some random AWS bucket that I guess they "own".
I haven't worked up the courage yet to install that, but here's the link to the support page wherein this is described, if you want to check it out for yourself:
https://kb.plugable.com/thunderbolt-3-docks/thunderbolt-3-su...
P.S. I should add that the initial X1C6 firmware had a bug where the laptop would rewrite the Thunderbolt... EPROM, or similar, on every boot. Resulting in Thunderbolt dying within a year for many people, when that memory device hit its lifetime write limit and failed.
I managed to dodge that, as my X1C6 sat in its box for over a year. Lenovo did eventually ship an update that was/is supposed to fix this behavior.
However, I get very leery about any update that might revert that bit of its firmware. Another reason I am, in a fairly uninformed fashion, hesitant to install the package that Plugable links to.
I don't know whether your T480 even shared this firmware problem, though. Nor whether my current hesitation vis a vis this situation is even justified.
USB4 devices can have a minimum of 20Gbps link speeds. In comparison, all Thunderbolt 4 devices have a 32Gpbs minimum requirement.
USB4 has a 7.5W minimum power delivery whereas Thunderbolt 4 doubles it with a minimum delivery of 15W.
With Thunderbolt 4, you’ll always get a minimum of 32Gbps and 15W.
Thunderbolt 4 cables support 40Gbps speeds over 2 meters. In contrast, UBS4 can only support 40Gbps within one meter and reduces to 20Gbps on cables that are 2 meters or longer.
I don't really game, but I would like to have a separate eGPU to hook up to my laptop for ML stuff, rather than have a GPU dedicated to a single box.
At some point it did just stop working.