As the others have said, 2.5Gb is there and pretty cheap, I just upgraded my entire setup at home, installed 4 2.5Gb switches in various locations and swapped out the NIC on my NAS for a 2.5 PCI-E Card.
All my cabling is cat5e and some of the runs are pretty long going through a few terminations, either at a wall socket or RJ45 end. The switches I have also have 10Gb SFP ports and I managed to get 10Gb working using 30m Transceivers, I was able to uplink two switches together using 10Gb, however it was kinda pointless and the transceivers were generating a crazy amount of heat.
I wasnt able to get 10Gbit though on one cat5e run because the feed was going from the switch via one cat5e cable, into a female wallsocket which is linked to another female wall socket, the two are linked with cat5e and then finally out of that socket into the switch.
As much as it will do 10Gb over a given length the conditions have to be optimal, so millage may vary but its definitely possible
Dont sweat it though, 2.5Gb is quite the upgrade over 1Gb and cost waaaay less to get up and running.
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