bitflipper
Whether it'll be of any use to us or not will come down to how configurable the feature is.
MS has been moving toward a design philosophy that intentionally minimizes user options in the name of fool-proofery. I expect that Game Mode will make many assumptions for you, such that it might not even be compatible with all games, much less your DAW. Version 1 could even be a disaster, it wouldn't surprise me.
One reason I'm skeptical is that MS just doesn't care about gaming under Windows anymore. These days all their efforts are applied to XBox development. Although Halo is their most successful PC game ever, they didn't even bother porting the last version to the PC. Why just sell the software when you can sell them a piece of hardware too?
This doesn't make sense anymore. As of Windows 10 the XBox and Windows desktop share the same Operating system from top to bottom. There may be a few more services enabled in the PC distribution, but the system is the same, so any optimization they do for the XBox also applies to the PC. I believe Microsoft initially developed this performance feature for XBox and have now just enabled it for PC and added a user customisation GUI
I would say this should be a very good feature for Pro audio, and I'd be surprised if they lock the system down for games only. Defining Sonar as a "game" should be quite simple, and hopefully they will also allow the users, and/or audio interface vendors to include the audio drivers in the high priority game process lists
However, this feature will probably just set process priorities, I don't believe it will actually disable system services. In other words a properly optimised DAW workstation that has services disabled will still perform better that any normal system with all the services processes running at low priority