server share hangs with windows7 network clients

I have a win2008 storage server with many shared folders on it. When an XP client tries to access those shares from the network, the directory listing is almost immediate. When a win7 client tries to access the shares, most of the time there is a lag of 10-20 seconds before a directory listing is displayed. The same is true when trying to establish an RDP connection.

I have disabled autotuning, heuristics, remote differential comp on both server and win7 clients with no effect. I temporarily disabled antivirus on server with no effect.

Any ideas would be welcomed.

Thanks,

John