[Samba] Low speed in Smaba sharing

[sam zand]

Hi dears,
how are you?

my friends, i installed samba 4.7 on centos 7 , i need to use Active
Directory in Samba,
i connect to sharing with windows client, through user and pass samba AD,

i use 1G ethernet connection between client and file server,

but when i copy a file  from windows to file server,
speed copy is about 30-50 MB/s (show in copy progress in windows),

while before i use from samba without AD , speed was about 110 MB/S,

what happen in samba with Active Directory that causes speed be low?

any way exist for solve it?

very thanks for your helpful answers,