From CockosWiki

ReaMote is REAPER's network FX functionality. It allows you to have any FX chain in your project processed on a remote machine on your local network.

This is very useful if you have a lot of CPU consuming effects and want to add more CPU power to your project without upgrading your main host's CPU.

Requirements

• Network bandwidth: Ideally, a 100MB or gigabit hub/switch will do fine. Depending on your sample rate and sample format you selected in the ReaMote preferences screen, you could process around 10-11 streams of 48khz stereo 64bits FX chains on a 100MB network.
• CPU: Any machine running Windows could do fine but first make sure that the ReaMote slave has enough processing power to run the desired effects.

Host configuration

Refer to the Preferences Plugins Reamote page for setting up and using ReaMote slaves in REAPER.

ReaMote slave configuration

To enable ReaMote processing on a slave machine, you'll have to first install REAPER and make sure the ReaMote option is enabled in the installer.

Then launch "Start menu -> Programs -> REAPER -> Reamote slave". There you go, your slave is now ready to process some FX data!