If you're using the same sound from a resource-intensive plug-in like a sampler in multiple patches, you can save RAM by copying and pasting an alias of the original channel strip. A channel strip alias doesn't duplicate the original plug-in, but refers to it. You can paste a channel strip alias into as many patches as you like.
Select the channel strip with the plug-in you want to copy and choose Edit > Copy. Then, create or select another patch and choose Edit > Paste as Alias. An arrow appears 
above the channel strip alias, indicating that it is an alias and not the original.
When you edit the original channel strip, all of its aliases change too. This is particularly useful when managing a large rig, in which making changes to dozens of patches can be time consuming.