If you're playing legacy games on your Windows machine, you'll be pleased to know that Microsoft has certain optimizations planned for them, especially if you're running them in windowed mode. The company has announced that Insiders on recent Dev Channel builds can now take advantage of these features.
Essentially, many old games use the "legacy-blt" presentation model to render frames on your display. Although DirectX 12 (DX12) already takes advantage of a new presentation mode called "flip-model", Microsoft is now rolling out this enhancement to DX10 and DX11 games too. The migration will improve latency and will also open the door to further enhancements like Auto HDR and Variable Refresh Rate (VRR).
The change primarily impacts old DX10 and DX11 games running in Windowed and Borderless-Windowed mode. Modern games using DX12 already benefit from this. That said, Microsoft has cautioned that:
When your game is configured to not use v-sync, this can result in a new frame being ready before the previous frame is displayed. At high frame rates, this may lead to screen tearing when this feature is turned on. To avoid tearing in your game, you can make sure to configure the game’s frame rate to match your monitor’s display refresh rate. Another option is to turn on v-sync in your game, which is often found in the game’s settings. If neither of those options work for your gaming experience, you can opt out of this feature and the instructions on how to do that are explained below. Another way to address tearing is by using a VRR monitor which can take advantage of the lower latency. However, please note tearing is still possible if you exceed the refresh rate of the monitor.
Microsoft says that the capability is available on Windows 11 Dev Channel build 22545 or later, which means that users on build 22557, that just rolled out yesterday, can take advantage of it.
You can head over to the Microsoft blog post here to find out how to enable the optimizations globally or for specific apps. It's currently unclear when, or if, these optimizations will be rolled out generally, both on Windows 10 and Windows 11.