9FPS with DX11, 25 FPS with DX10 preview. Why?

If DX11 and DX9 are backwards compatible, why am I getting such crappy frames with DX11? It boggles my mind. Thanks!

FSX doesn't use DX11.

Some informational reading on DX11 compatibility...

 

The light:

http://answers.microsoft.com/en-us/windows/forum/windows_other-gaming/is-directx-11-backwards-compatible-to-directx-9/c41fab41-2c95-4164-89f6-5f130d9ec7a6

 

https://answers.yahoo.com/question/index?qid=20120705094848AAqUG55

 

http://www.tomshardware.com/forum/285432-33-games-dx11-hardware-windows#6880700

 

The medium:

DirectX11 and WIndows 8.1:

"For the most high-fidelity and rich experiences in 3D games, you’ll want to use the Windows 8.1 DirectX APIs. This is the easiest version of DirectX to develop with. It supports a wide range of graphics feature levels, from DirectX 9.1 to all the latest hardware features exposed in DirectX 11.1. It allows you to tailor your game to every PC, from power-efficient ARM-based portable Windows 8.1 tablets, to over-clocked multi-GPU gamer rigs."

https://msdn.microsoft.com/library/windows/apps/hh452744

 

I've seen posts to the effect that the above is proof DX11 support 9.1 but not 9.0c. The above is referring to the DX11 SDK and programming, not necessarily to the capability of the runtime DX itself. So, my belief is when using the DX11 SDK as a PROGRAMMER, you are not going to be programming DX9 games with it.

 

http://steamcommunity.com/app/261760/discussions/2/540736965900645494/

 

The heavy:

http://en.wikipedia.org/wiki/DirectX

 

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My understanding is when you install a DX9 game (like FSX) that also automatically runs the DX9 installer, it checks for file versions (which takes a while because there are many files associated with DirectX) which ultimately replaces nothing on a DX11 system and exits.

 

I have seen posts which state DX11 is not compatible with DX9. These claims might be based on HARDWARE compatibility. It is true that DX11 cannot command certain older DX features built into obsolete cards.

 

Occasionally I see posts where the user says the game will not run under DX11. The program error states something to the effect "Directx version 9.0c or higher is required to run..." and similar verbiage even though they have confirmed their system is DX11. When others suggest DX11 is not 9 compatible and they need to run the full install of DX9, this results in a failure.

The true issue here is one or more of the HARDWARE components of the system is not DX9 compatible which cannot be solved except through replacing hardware or drivers or firmware.

 

Testing 101:

FSX is a semi-radom environment. It's possible for frame rates to go up and down radically between test runs for reasons which have little or nothing to do with system capability, drivers, etc. For the serious investigator, I have posted other threads on how to obtain stress test conditions where the most of the random FSX features are minimized.

 

Regardless of whether you use DX9 or DX10 preview mode (with or without the DX10 shader replacements) FSX is bound by the speed of your CPU (as all *3D* games are to one extent or another.)

 

-Pv-