In DxDiag, the General tab reports DirectX10. On the Display tab, it reports DDI Version: 9Ex. This is using the latest nVidia 64-bit Vista reference drivers and August 2008 DirectX redistributable in Windows Vista Business x64.

Microsoft Support says that it's a known issue but it doesn't affect performance: http://support.microsoft.com/kb/939998

Unfortunately, that's incorrect. Some programs are apparently using the DDI Version to determine the level of DirectX capabilities. It does affect performance in those situations.

Other programs seem to be able to detect DirectX 10 in other ways and allow me to use DX10-only features. The DX10-only samples in the SDK run without complaint.

The video card is 2x nVidia 8800 GTX in SLI. (It does this even with SLI disabled.) Driver version is 7.17.11.7519 (175.19) for nVidia Series 8 on Vista x64.

A friend has a single 8600 GT with the same driver, and the DDI version is reported at 10. Those programs allow the extra DX10-specific options on his machine.

I have tried uninstalling the video driver, rolling back the video driver, reinstalling the video driver and reinstalling DirectX August 2008. The registry has the DX10 DLLs properly registered for 64-bit and WoW along-side the DX9 DLLs. The DX10 DLLs are the same DX10 DLLs on my friend's computer.

Does anyone have any ideas what is causing the problem and a fix? Is there a way to force the DDI version to report 10 until a fix is available?

Thanks in advance!

The right way to detect DX10 is to attempt to create a DX10 device. If it works, you've got DX10.

A program that uses some other mechanism for detection, is a buggy program. You'll have to ask the publisher of that program for a patch/fix.

 

Thanks! I submitted a bug to the developers regarding this.

 

Is there a workaround to make it report 10 instead of 9Ex until then?