The 2.5GbE ARM SBC's I mentioned are both RTL8125BG and seem to use Linux kernel module r8169
I just had CAT5e cable between them, same as for 1GbE. CAT5e can handle 2.5GbE (or 250Mhz AFAIR) up to 100 meters.
Also note that RPi3B+ also negotiates at 1GbE, but you only get about 350Mbps and physically half duplex as USB2 based.
USB objects in between, even though USB3 HW/spec, risk some old SW stack architecture that might come from USB2, so bidirectional pipe-lining might not be optimal. Is a guess, have seen that long time ago in early USB3, should be no issue nowadays anymore I assume.
I just had CAT5e cable between them, same as for 1GbE. CAT5e can handle 2.5GbE (or 250Mhz AFAIR) up to 100 meters.
Also note that RPi3B+ also negotiates at 1GbE, but you only get about 350Mbps and physically half duplex as USB2 based.
USB objects in between, even though USB3 HW/spec, risk some old SW stack architecture that might come from USB2, so bidirectional pipe-lining might not be optimal. Is a guess, have seen that long time ago in early USB3, should be no issue nowadays anymore I assume.
Statistics: Posted by redvli — Thu Jan 08, 2026 7:45 pm