However, a newer version of CAT5 cable in the market, CAT5e, can support up to 100/1000 Mbps at a 350MHz bandwidth. In comparison, CAT6 can support up to 1000 Mbps (1GbE) at a 250MHz bandwidth. ... CAT6 cable has a thicker diameter around 0.250-inches maximum while CAT5e cable has a smaller diameter around 0.204-inches.