I have a CAT6 cable plugged into an RJ45 SFP+ transceiver on my CRS305 switch, but I noticed the transfer speed were abysmal. After doing some digging I discovered that the switch was reporting the negotiated speed as 10Gbps even though the client was only 2.5Gbps (also tested on a 1Gbps client). I am on RouterOS v6.45.6. I tried disabling auto-negotation and specified 1Gbps on both switch and client (Windows), but I couldn't establish a link.
Any idea what's going on here? Thanks