with ontap 7.3 you have smb2, "options cifs.smb2.enable on"
to increase sequential throughput you have to increase the TCP windows size, its in the "options cifs" as well. be aware that after increasing the window size you need to "cifs terminate; cifs restart" and reboot your client to be 100% sure all is fine.
usualy i do not recommend on doing so as speeds of 40 to 60mb are just fine and its more important to offer plenty of clients average speed then a single client full speed.
Re: Probs speed windows 7 x64, windows xp, server 2008 r2 FAS2020