So having used X-Plane 11 for a while now and spent a number of hours tweaking it to get the most out of it. I thought I'd share for those of you either using X-Plane 11 or planning to try it out, how to go about getting the most fps and eye candy out of it as possible.
PART 1 - GENERAL SETTINGS, WHAT AND HOW
When you're tweaking for performance vs. eye-candy the first thing you want to do is to start up a flight which best demonstrates your average flight situation, such as scenery location and aircraft most used. Then set the weather conditions to have a lot of clouds as this hits the frames a lot.
Then have X-Plane display your frames by opening your Settings window up on the right. Go into Data Output and the first item there is Frame rate, set it to Show in Cockpit.
This renders you frames and fps related items in real time.
f-act = your actual frame rate per second
cpu = process wait time that is CPU (computer CPU) based
gpu = process wait time that is GPU (Graphics Card) based
To get 30 f-act fps both of these need to be pretty much stable at 0.03.. or below.
The higher the number for cpu or gpu means that it is taking longer to finish whatever process the flight sim has thrown at either your CPU or GPU.
So if for example you have a very powerful graphics card but an older computer with an older cpu, odds are your cpu meter is going to be quite a bit higher than your gpu meter. This means the graphics card is done with whatever it was told to do, and before rendering a new frame (for fps) you're waiting for the cpu to finish whatever it needs to do. Thereby you've identified your bottleneck as being your cpu.
Now the good thing about finding out this information is that it enables you to modify your settings accordingly. Some processes such as auto generation of buildings is a lot more CPU dependent, whereas enabling HDR and anti-aliasing at higher levels is more GPU dependent.
If you hover over the various graphics settings in the Graphics window under you Settings window, it will tell you whether that particular item is tough on the CPU or GPU.
So now that know how to tweak your simulator by keeping an eye on your FPS, CPU and GPU performance this will take you a long way.
Another thing to note is that X-Plane requires a lot less frames to fly smoothly than you would expect in FSX and Prepared 3D.
40+ fps = some studies have indicated that at this point your mind stops feeling like it's flying a sim but that you're actually flying
30+ fps = very smooth and pleasant experience, the suspense of flying is there
25+ fps = still alright, and can still fly without any problems, mainly notice the lower fps when panning the view or moving quickly
20+ fps = noticeable fps issues, can be tiring on the eyes and can feel unresponsive
20< fps = need to get those fps up a bit higher
If you’re getting very high frame rates overall but the experience does not feel smooth, you might want to try enabling “Use Vsync” in the Graphics settings, as this may lower your average fps but smooth the frames delivered out.
PART 2 - PLUGINS FOR BETTER PERFORMANCE
I've found one add-on that makes a MASSIVE difference, in the range of 10-15+ fps and enabled a lot of more autogen etc. to go with that.
To use it you need to add the following plugin to your X-Plane 11 \Resources\plugins folder:
After that is done download the following plugin:
Lua Environment booster XP11: http://forums.x-plane.org/index.php?/files/file/36188-lua-environment-booster-xp11/
You can pick what you want from it, but what really improves the performance is the FPSBoost.lua script!
Just take that and copy into your X-Plane 11 \Resources\plugins\FlyWithLua\Scripts folder.
You can reload your lua scripts in flight while experimenting using the in-game Plugins menu item, otherwise they automatically load on restart.
I found another similar fps boost by adding the Environment.lua script as well, so those two together more than doubled my fps, which was amazing!
But for now I'm doing without the environmental.lua as I prefer the clouds without it (then again I haven't tried the replacement textures etc. so might just look even better, I'll try that another time).