I think you are talking about File copy performance. If this is the case then ideally in between 2008r2 and Win7 you should get good speed since they use SMB2, SMB2 is faster as compared to SMB1.
Things that you can do
1. Make sure that the following file are updated to the latest version ( srv.sys, Mrxsmb10.sys , Mrxsmb.sys and rdb.sys)
2. Navigate to HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\Memory Management and create PoolUsageMaximum
On the Edit menu, click Add Value, and then add the following registry value:
Value name: PoolUsageMaximum
Data type: REG_DWORD
Radix: Decimal
Value data: 30
3. Follow this blog http://social.technet.microsoft.com/Forums/en/winserverfiles/thread/34b11569-1910-43ce-a6b2-fc73b4cf07f0
This would definitely increase the server performance.
From SEPM side you can disable network scanning but it would not have much impact. When an AV is installed it adds some overhead. Above are the OS tuning that would/should help