@cmb:
scp is a "very slow" protocol, it's designed to be secure, not fast. Getting 70 Mbps may well be the best you can do. You're not going to max out any hardware resources when doing a scp transfer generally. Google "scp slow" and you could spend months reading the results. Windows is worse if it's your client, OS X, BSD and Linux clients will be faster, but still nowhere near as fast as the hardware resources can transfer.
Thanks a lot. I was just wondering why. I even used jumbo frames at 9000.