Originally Posted by westcoaststyle
CAT6 cable contains four pairs of copper wire and unlike CAT5, utilizes all four pairs. CAT6 supports Gigabit (1000 Mbps) Ethernet and supports communications at more than twice the speed of CAT5e, the other popular standard for Gigabit Ethernet cabling.
Cat 5 and Cat 5e both have 4 pairs also. And yes you can use them all. It's the interface that you plug it into that chooses to use them all or not... not the cable. Cat5e is also rated for 1000Mbps+ speeds, but right now the only thing actually being used that is faster is optical.