I open Windows Explorer and enter an IP for a computer on my home network (\\192.168.1.101). It takes 30 seconds or more to present a list of the shared folders. It does not appear to be an initial handshaking/authentication thing; even if I allow the view to load and then immediately load the same again, it is always slow.

Once they appear, navigating through folders and opening files is fast. Also, navigating directly to a folder (\\192.168.1.101\My Music) is fast, even if it's the first connection since a restart.

Using \\computerName instead of the IP address gives exactly the same results.

Pings return in 1ms.

net view \\computerName (or \ipAddress) returns the list of shared folders fast. This makes me suspect an Explorer issue rather than a network issue.

Suspecting that the remote computer was being automatically indexed or something, I went into Tools->Folder Options->View and unchecked "Automatically search for network folders and printers," but that made no difference.

De-selecting the "Folders" icon near the address bar makes no difference.

Adding the IP address and computer name to the hosts file makes no difference.

Both computers involved are laptops running Windows XP. Both have WiFi and cable adapters. Mine is not connected via cable. The result is the same whether the target is plugged in to the cable or not (although the IP address changes - 192.168.1.101 over cable, 192.168.1.103 over WiFi.) We are using DHCP assigned by the router.