KB 935755 - You cannot access a shared network resource that is hosted by a Windows Vista-based computer if the SMB request packet exceeds the MTU size

Very interesting insight into possible network stalls and slow file copies problems with Vista as a SMB file host.

SYMPTOMS
You cannot access a shared network resource that is hosted by a Windows Vista-based computer if one of the following conditions is true:

1. The size of the server message block (SMB) request packet exceeds the maximum transmission unit (MTU) size of the requesting device.
2. The size of the SMB request packet exceeds the MTU size of the router that connects the requesting device with the server.

CAUSE
This problem occurs because the server does not respond to an SMB request if the SMB request packet is fragmented. The SMB request packet is fragmented when its size exceeds the size of the MTU.

A hotfix is available for this.