My Carenado planes cause X-plane to run at low frame rates. What can be done to fix this?
As time goes on, Carenado is using increasingly more hi-res textures, in order to satisfy the ever-increasing demand for detail. However, numerous hi-res textures and detailed 3D meshes, as well as increasingly complex plugins do require a powerful computer to run them.
X-Plane.com has published MINIMUM system requirements, as well as RECOMMENDED system requirements for the simulator itself here. What is important to understand about this, is how VRAM affects performance in the sim, especially when flying complex HD aircraft.
Every video card has its own memory, denoted as "VRAM." Laminar Research recommends 1 GB of VRAM to run X-Plane 10 smoothly, but it may be that with the addition of a HD Carenado plane, the total memory usage climbs to beyond that available GB of VRAM. Carenado also states a recommended VRAM requirement of 1 GB for its latest planes, but it's important to become familiar with how these system requirements are to be understood.
When the textures and 3D objects loaded into the sim (Yes, this includes scenery as well) exceeds the limit imposed by the amount of the video card's VRAM, the overflow gets diverted to the computer's physical RAM, which is many times slower than VRAM. Since the sim only runs as fast as the slowest link in the chain, it is crucial to NEVER exceed the amount of your system's VRAM in X-Plane's rendering settings.
The most effective way to fit large amounts of textures (which is the case with the HD-series of Carenado planes) into the available VRAM is, to use texture compression and to reduce the texture resolution. This can be done in X-Plane's "Settings>Rendering Options" window, and is outlined in a PDF document included with Carenado's aircraft.
At the bottom of the "Rendering Options" window, there's a text line that indicates how much video memory is required to run the sim at the current settings. If that number exceeds the available VRAM your system has, you can lower the "texture resolution" settings, in order to fit it all into your system's VRAM.
Carenado's latest v10 planes have a special protection on CERTAIN textures, protecting those from resolution degradation as the "Rendering Options" are lowered. This means, you could set the sim to "Minimal" texture resolution. After a restart, you would notice that all the textures of the surrounding world, as well as the plane's exterior, are very fuzzy and low detail, but all the interior textures that matter for flight (all textures containing text, instrument values, etc.) are crisp and clear. This allows you to still use Carenado's planes in v10, even if your computer does not technically meet the system requirements.
In fact, it has been found that with this new feature, people can still use Carenado's planes in v10, that they would NOT be able to use effectively in v9 with that same hardware and VRAM configuration. Provided, of course, that the user is not overly concerned with a beautlfully detailed landscape and aircraft exterior. At the lowest settings, Carenado's planes can still be flown quite well at decent frame rates with a 256 MB VRAM video card in v10.
All future Carenado planes will have these optimizations, effectively lowering VRAM requirements. All updates to the older planes, once they get published for v10, will also have these optimizations.
However, Carenado recommends considering the use of video cards that have "room to grow," as future planes will continue to use more hi-res textures. This will allow simulator enthusiasts to get the most out of the planes they purchase.