(Source: http://social.answers.microsoft.com)

Disable Remote Differential Compression

• Click Start – Control Panel – Programs – Turn Windows features on or off
• Uncheck Remote Differential Compression and click OK
• Restart the computer and you should see an improved performance with copying files.

Disable TCP AutoTuning and Receive Side Scaling

• Open an elevated command prompt with administrator rights.
• Type the following commands and press Enter (the second command on RSS is optional):

netsh interface tcp set global autotuninglevel=disabled
netsh interface tcp set global rss=disabled

Reboot the computer

Create a folder on your desktop and call it this:

GodMode.{ed7ba470-8e54-465e-825c-99712043e01c}

It will give you immediate access to all configuration settings/tools for Windows 7.

This allows a connection from the COMPUTER1 to the COMPUTER2 computers.

Additional configurations

Router Port Forwarding

On the Linksys router, I setup port forwarding for TCP/UDP traffic on port 1723 to forward to the COMPUTER2 computer.

Firewall

On the COMPUTER2 computer, I setup a firewall rule to allow INCOMING traffic on port 1723. I made it specific by allowing only my user account to do this.

Antivirus

Some people report issues with their antivirus and/or internet security software blocking traffic. Avast seems to be ok.

Problem

I’ve tried different thumbnail sizes and it doesn’t seem to matter what size it is, it just has problems loading thumbnails. The more pictures that are in the folder, the worse it is. I know Explorer wasn’t really designed to handle loading thumbnails for 10,000+ pictures, especially over a 100 MBit network connection… but this is really bad in comparison to Windows XP Pro. I never had these excessive thumbnail load times in XP. Read more »