umm.. link speed is everything if you want to transfer faster than 100mbit. Not sure i get what you mean by saying it's meaningless. Could you explain so i understand where you are coming from.
i had issues with the VM hub not negotiating 1000gbit with my AC88U. they negotiated at 10/100 (100mbit), so my transfer speeds were being limited due to this error of negotiation between the 2 bits of hardware. Known good CAT 6 cable, it had also been working fine for almost 2 years before i had to do a factory reset of the VM hub - just saying it wasn't a cable issue.
resolved with another reboot though.... but still...
TLDR; link speed does actually matter
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