Last month Microsoft confirmed that a new "Game Mode" would be part of the upcoming Windows 10 Creator's Update planned for a spring release ("early 2017"). Microsoft has recently started rolling out the Game Mode to its beta testers in the latest Windows Insider preview build (for those on the fast track anyway, I am currently on the slow ring and do not have Game Mode yet). Now that it is rolled out in preview form, gamers have naturally started benchmarking it, and PC Games News has posted an article on their testing of the new feature and their findings on two Win32 and one UWP game. Not to spoil the results, but at this point Game Mode does not appear to offer anything and can even result in less frames per second with it turned on with its only saving grace being that in some situations it does offer increased performance when the Game DVR feature is also being used to record gameplay. They tested both a NVIDIA GTX 1060 and an AMD RX 480, and Game Mode in it's current preview software on a preview OS appears to have more benefits for NVIDIA while the AMD card PC Games News tested mostly just did it's thing regardless of whether Game Mode was turned on or off (heh, not necessarily a bad thing).
With Game Mode now rolling out to Windows Insiders, there is more information on how Microsoft plans to implement it. Rather than hiding it in the Xbox app, Microsoft has thankfully put it in the main settings app under the Gaming category and users access it by bringing up a Game Bar menu in-game for those games that support it (PC Games News noted Doom and GTA V did not work). Game Mode is an OS-level feature that will dedicate a certain amount of CPU threads to the game when it is turned on and leaves the remaining threads to be used by background processes (which themselves are reportedly minimized). Currently, this seems to work better with multi-threaded games and older games that were coded to only use one or two threads may not see any benefit in turning Game Mode on (and it may actually result in lower FPS). To Microsoft's credit, they are not over promising with Game Mode and note that it should be good for around 2% better performance when enabled with Game Mode having a bigger impact on UWP titles.
I encourage you to check out the PC Games News article where they have their benchmark results presented in a number of bar graphs. Most of the tests saw little to no benefit from using Game Mode, but not a negative effect. Some games like Hitman saw a 6% increase in average frames per second on the GTX 1060. On the other side of things, Forza Horizon 3 (ironically, a UWP game) performance actually drops when Game Mode is turned on to the tune of 13% to 23% less FPS with the RX 480 and 9% to 15% less with the GTX 1060. As far as Tomb Raider, things are more in the middle and things stay the same or get slightly better minimum frames per second when Game Mode and Game DVR are both turned on (though oddly there is a result in there that shows a performance drop with Game Mode on and Game DVR off).
It ia also worth noting that overall, the trend seems to be that Game Mode is going to be most beneficial at increasing the minimum frame rates on games with the Game DVR feature is being used moreso than getting overall maximum or average FPS out of a game. The biggest hurdle is going to be game compatiblity, especially for older games, and Microsoft tweaking things so that at worst Game Mode won't tank performance (like it currently does with Hitman minimum frame rates when Game Mode is on but DVR is off) and things will stay the same as if Game Mode was not on at all and at best gamers will get slightly smoother gameplay.
Right now Game Mode is not compelling, but it is still a work in progress and if Microsoft can get Game Mode right it could be a useful addition (and incentive to upgrade to Windows 10 is probably why they are interested in pursuing this feature) and could come in handy especially on gaming laptops! I am not writing off the feature yet, and neither should you, but I do hope that compatibility is improved and the performance hits are reduced or eliminated when it is enabled. My guess is that the games that will work well with Game Mode are going to be almost all newer games and especially games that are developed post Creator's Update final release with Game Mode in mind.
Hopefully we can use our frame rating on the final product to see how well it truly works as far as user experience and smooth gameplay. What are your thoughts on Windows 10's Game Mode?