PMFJI, but this may help:

>>>Might be oplocking not disabled: caches the single user PC somewhat.
>how do I disable oplocking? SMB2 is disabled is that the same?
>

http://oplocks.net/how-to-disable-win32


Multiuser system speed

1. Set OPLocks off for increased speed in multiuser systems

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MRXSmb\Parameters\

set OplocksDisabled = 1

OplocksDisabled REG_DWORD 0 or 1
Default: 0 (not disabled)

2. HKLM\System\CurrentControlSet\Services\LanmanServer\Parameters

SharingViolationRetries REG_DWORD 0?1000 attempts

Default: 5

Determines the maximum number of times the Server service attempts a file operation when the file system responds with a sharing violation error. If a client requests more attempts that the value of this entry allows, the Server service returns an error. This value entry applies to open, rename, and delete operations.

Note

Windows NT does not add this value to the Registry. You can add it by editing the Registry or by using a program that edits the Registry.

SharingViolationDelay REG_DWORD 0?1000 milliseconds

Default: 200

Determines the time interval between repeated requests for a file operation when the file system responds with a sharing violation error. This value entry applies to open, rename, and delete operations.
Decreasing this value (requesting more frequently) increases network traffic. However, increasing this value (requesting less frequently) might delay users unnecesarily.

Note

Windows NT does not add this value to the Registry. You can add it by editing the Registry or by using a program that edits the Registry.