Can anyone tell me if you gain any performance in add-on scenery (or scenery in general) by using the option "Cache this scenery" rather than "Use this scenery directly"? Also, should the cache amount be equal to RAM or space on disk?Any help or insight would be greatly appreciated!

The scenery cache is only meant for caching scenery loaded from CD on partial FS installs. Do not enable it for third-party scenery, or for full installs, as it degrades the performance by copying files to a cache folder before using them--basically a redundant step if all your scenery is already on the HD. As long as no scenery is cached, the cache amount is ignored. -John