File server client very slow NBU 7.6.0.4

Hi all,

I have NBU 7.6.0.4 making backup to storage disk, many clients windows 2008 R2 and 2012 R2, only one client 2012 R2 is very slow, the other clients speed is about 17000 KB/sec, but this one it no pass of 300 KB/sec.

Can anybody help me?

Thanks.