samba - Jul 2015 - 41-4.1.7 stops responding from Windows Server 2008R2

Hello All,
I have share on FreeBSD 10.1 64bit to a cluster of Windows Server 
2008R2. During the busiest time of the day, share stops responding. 
restarting samba on the FreeBSD restore the service.

has anybody experience similar issues? any ideas or suggestions?

Thanks,
Motty