Native DX9 hardware support is officially gone from Intel’s Xe integrated graphics solutions on 12th Gen CPUs and A-Series Arc Alchemist discrete GPUs. To replace it, all DirectX 9 support will be transferred to DirectX 12 in the form of emulation.
Emulation will run on an open-source conversion layer known as “D3D9On12” from Microsoft. Conversion works by sending 3D DirectX 9 graphics commands to the D3D9On12 layer instead of the D3D9 graphics driver directly. Once the D3D9On12 layer receives commands from the D3D9 API, it will convert all commands into D3D12 API calls. So basically, D3D9On12 will act as a GPU driver all on its own instead of the actual GPU driver from Intel.
Microsoft says this emulation process has become a relatively performant implementation of DirectX 9. As a result, performance should be nearly as good, if not just as good, as native DirectX 9 hardware support.
This DX9 change from Intel appears to be a very good move as a result. Intel can now divert driver development resources towards DirectX 11 optimizations — which we know is very bad at this time, and Intel won’t suffer performance consequences as a result, with DX9 optimizations “outsourced” to Microsoft entirely.
According to Microsoft, with how performant D3D9On12 is, it will be interesting to see if Nvidia and AMD follow the same path as Intel. But, there could be consequences to the API translation, including higher CPU usage (since the translation is software accelerated) and potential side-effects with older games. Nvidia and AMD also have almost 20 years of driver experience with DirectX 9, which might result in performance losses with the DX12 emulation layer.
Intel, on the contrary, only has experience with DirectX 9 on its integrated graphics, which does not translate into the experience with its much higher-performing discrete graphics. So it makes a lot of sense that Intel is immediately transitioning to emulation as it gets closer to launching Arc worldwide.