[Samba] Perf enhancements in Samba4.1 related to SMB2.1 / SMB3.0 protocol

[sp bglr]

Hi Everyone,
My doubts are for Samba4.1  performance related enhancements (SMB2.1 / SMB3.0).

My experimental samba server hardware  is running 4.1 version. Want to
improve robocopy WRITE  throughput from a two samba client machines
(win7 or win8 or server2012  x86 servers).

Someone please advice me how can I use SMB2.1 or SMB3.0 capabilities
to improve WRITE throughput.  I tried samba4.1  earlier but not seeing
any WRITE MBps  going up  (compared with samba 3.6.8 on same
hardware).

To enable SMB2.1 or SMB3.0  perf. enhancements  please suggest if
1) any thing(s) need to be added in smb.conf or
2) need to compile samba4.1 with some special options or
3) samba client systems need some tuning
4) or any other pointers

Thanks in Advance
Regards
Bglr