hi aivenhoe, dont know if it could help:
but for hudges patches, i m now switching off ( node) the connection to the final renderer.
By doing a bang togedged up to a toggle, i m switching on manually, once all the patch is opened the group(ex9) to texture. This seems to save a problem of memory with renderers full screen. Dont know if this trick will help you, i hope so, as joreg mentionned a memory problem.