The difference between Cat 6 Cable, Cat 6a and Cat 5 cable is the performance and available bandwidth. A standard Cat5 cable has runs at about 100MHz and Cat 6 runs up to 250MHz. Cat 6 has pretty much over double the speed for transmission compared to Cat 5. You could also take it a little further by going with Cat 6a that runs up 550 MHz, over four times as fast as Cat 5e.
Some of the reasons why Cat 6 is able to achieve this because of better near end cross talk (NEXT), equal level far end cross talk (ELFEXT) and better insertion loss. Cat 6 cable also has higher signal-to-noise ratio which provides better reliability for demanding application now and in the future. Cat 6a is able to achieve this through grounding the cable and shielding the individual pairs, by doing so the amount of interference and resistance is drastically reduced.The Cat 6 cable will provide your network with less errors and fewer re-transmission loss and/or corrupted data packets because Cat 6 is more resistant to external noise and provides better transmission performance than Cat 5.