SPrepar3D v4 settings
First of all, in the display page, increasing antialiasing settings is important if you want to have a high image quality without jagged edges. Mine are set to the max but I encourage you to test different settings depending on your GPU as this can have significant impact on the performance of the simulator.
Then in World page, basically all sliders are maxed out in the terrain and Scenery Objects sections except the Autogen Draw Distance as the range has been increased in the v4.4 release. Very high is more than sufficient for me as I always have limited visibility and haze in my weather settings.
As regards Water and Bathymetry, I set the details to high and checked the Enable Bathymetry box to allow for more realistic rendering of water surfaces.
In the lighting page I enabled HDR and set the settings to work with my TomatoShade preset (see next section).
I don't use dynamic lighting for the time being but you can check this box if you want to have a more realistic lighting in scenes that use that function.
Regarding shadows, I would recommand to be parcimonious as this can also take a significant toll on your framerates...
TomatoShade is standalone program that allows users to access the P3D shaders and change the default settings. Shaders are very important in 3D applications as they basically tell the GPU how to interpret the insructions given by the rendering engine of the simulator. By default, the shaders are set to accomodate a wide range of displays and are therefore quite neutral in term of rendering. You can use a predefined preset or create your own by changing the different parameters.
You can download the latest version of TomatoShade (v27 and above for compatibility with v4.4) at this link and unzip the file. In the resulting folder you can click onTomatoShade.exe file to launch the tool. Once loaded go to General and Check for new version so that you can update to the latest version.
Then you can look at the different menus to change the clouds, lighting, atmosphere & fog, water and HDR parameters
If you want to use my preset, you can download it here
You just need to change the file extension to ini instead of doc and go to the File menu in TomatoShade and click open.
Once the preset is loaded, go to the Actions menu and apply or just press F9 to configure the Shaders with the new preset.
You can now launch P3D to see the difference. Don't worry the if the screen remains black for a few seconds once you load the simulator just after applying a new preset, that is normal as the cache was cleared and so the new shaders have to be rebuilt.