I have hard time to select between Thinkpad P50 and P70 due to amount of thunderbolt ports. What is advantage of having dual thunderbolt ports at P70 over one thunderbolt port at P50? I understand more port allow you to connect more device with more performance. but since each thunderbolt port can connect to 6 child device. What I might be missing in future if my device have 1 thunderbolt port? Or What dual thunderbolt port can do that one thunderbolt port can not do?