Use below option.
"options cifs.tcp_window_size 64240"
You can also try with enabling oplocks, I have tried to add some information
on it below.
BTW have you tried looking at volume settings to increase performance, like
minra, at time update or settings on client side.
cifs.oplocks.enable:
Oplocks (opportunistic locks) enable a CIFS client in certain file-sharing
scenarios to perform client-side caching of read-ahead, write-behind, and
lock information. A client can then read from or write to a file without
regularly reminding the server that it needs access to the file in question.
This improves performance by reducing network traffic. CIFS oplocks on the
filer are on. By default: You might turn CIFS oplocks off under the
following circumstances otherwise, you can leave CIFS oplocks on.
1. You are using a database application whose documentation recommends that
oplocks be turned off.
2. The CIFS clients are on an unreliable network.
3. You are handling critical data and you cannot afford even the slightest
data loss.
-Sent from my handheld
