Always full, half will give you 500kb/s (approx.) or 5000kb/s (approx.) depending on whether you do 10 or 100mbit, and full will do 1000kb/s (approx.) or 10000kb/s (approx.), it has to do with being able to send and recieve at the same time, half means that it will only send, or recieve, but not both at one time, full does both constantly.