GB Network performance is slow with SMB(45MB/s) compared to FTP (105 MB/s).
Any hint how to improve?
On your Server 2008 R2 machine I would run these commands one at a time from an elevated command prompt (if you haven't already disabled UAC).
Then reboot your server and test performance again. I know in my own experience this has vastly improved network speeds.
Hope that helps.
Have you tried using an NFS share? , while this doesn't help smb at all I find it faster on my Openfiler server. 10.6 and 10.7 also makes it easy to mount an NFS share with disk utility.
On a side note, do you have severe finder lag while browsing the smb share? It was so bad with 10.6 and server 2000 that I could find files faster in terminal!