i've got
two 10Mb roadrunner connections, and two nics on my pc. If i mess around with the metrics i can get it to use both at once in certain programs, but it's a real pain, and only works with a very few, download managers basically.
so... yeah, it will help. i know

if i could assign steam or my download manager to one nic/rr account, i can then stream netflix or youtube on the other, and have full quality and speed on both!