Cat 5 can handle 10/100 Mbps speeds (Fast Ethernet) at up to 100 MHz bandwidth. That's a lot of numbers, but what it means is "slow and obsolete". New installations don't even use it, and it's on its way out, sadly...that's sadly for the cable, not for you. For the savvy cable connoisseur there are newer, better, faster, stronger options out there. Companies use Cat 5e or Cat 6 cable now.