Is there any value added to unchecking scenery boxes (located in initial startup settings)when you aren't flying in that area? For example, should I uncheck ultimate terrain Europe if I'm flying mainly in the US? Are any system resources being allocated to "maintain" checked scenery even though you're not "loading" that scenery/texture set?Lastly, with regard to scenery settings, what does priority actually mean? What's happening when I designate a scenery set (eg., ultimate terrain US) as number 1 vice number 5? If there is a method, how do most folks rack and stack? Is there any correlation between the priority and performance (FPS)?ThanksKemoF15

Mainly what I have observed from using sysinternals procmon, is that addon scenery object libraries are accessed over and over, even if they are intended for local areas (rather than the more universal ones like rwy12). I'm not sure that unchecking local areas with libraries would have a measurable impact on performance, though.As far as scenery priority, it is mainly an issue of the scenery exclusion capabilities offered for addon scenery. In general, a scenery exclusion will remove all scenery objects of a given type and within a given area that are placed in lower priority scenery areas. In a few cases there can be an implicit exclusion, essentially the highest priority file of the type "wins". In many cases, though, scenery from different priority levels will coexist, and priority level is immaterial.Priority grouping can help in keeping order for administering addon scenery, aside from any possible visual or performance effect. As a general matter, I tend to place small-area scenery at a higher priority, under the assumption that small area are modeled with higher fidelity and more accurately placed scenery than regional or world-wide scenery. Hence I want any exclusions that might exist in the small area scenery to operate on the regional or world-wide scenery.I recommend looking at any readme included with an addon, and either following the advice for placement, or at least trying to understand the intent, so you can intelligently determine the best placement for your system. scott s..

Thanks Scott for the informative reply.KemoF15

Here is a good explination regarding Scenery Levels.Dick ReaMCA372

Thanks Dick---good stuff!KemoF15