Hi @iqbalwiawan -
50-80 mbps is the typical maximum speed possible with the Fathom-X two-wire ethernet adapter. Making sure your two wires are the exact same length, and twisted together consistently along the entire length can help improve this! Using a co-ax cable is also possible, but not likely to improve bandwidth above 80mbps, and is also typically more fragile than Fathom tether…
If you need higher speeds, a more modern homeplug adapter could do the trick!