I haven't followed the topic fully but is there a scenario where you would recommend disabling fullscreen optimizations?
It mostly seems to be an issue for people that are wanting to downsample games, as you sometimes need "real" exclusive mode for it to change the display resolution.
Also, since you mentioned it is it a good idea to leave game mode enabled? I can't test it at the moment but last I tried it made videos/streams stutter pretty badly on secondary screens whenever I played a fullscreen game. So I'd gladly take multitasking over any miniscule performance gain, if that's the case.
Game Mode has largely been cancelled by Microsoft.
In older versions of Windows 10 what it did was reserve 3/4 of the available CPU cores to the game process, and move all non-game processes over to the first 1/4 of the available cores.
Here's an example of it in action, with me forcing an undemanding game to only run on core 15 while also running software in the background to put some work on all cores.
Game Mode Off. CPU usage is split evenly across all cores:
Game Mode On. All non-game processes are moved to the first four cores, with the rest reserved to the game (which was overridden to only run on core 15):
Though there were some issues with it, it was a great feature in my opinion - particularly in games which are bottlenecked by a single thread.
For example:
SOMA runs most of its game logic on a single thread.
That means Game Mode provided a significant amount of headroom. Without it there was only 6% of a core free, so it was likely to drop frames if a more complex scene appeared or if CPU usage increased in one of the background programs.
With Game Mode enabled there was 22% of a core free, and the core was reserved so increased background application activity could not affect it - so even more demanding scenes would not drop frames.
The problem with Game Mode can be seen in that first example where the game is only running on core 15 though.
See how the first four cores are now hitting 100%? For whatever reason, certain critical Windows processes will only ever run on core 0. That includes things like interrupts, which affect your input devices.
If you had a lot running in the background, Game Mode could potentially put so much load on core 0 that it would cause the system to become extremely unresponsive; only responding to inputs every few seconds.
Or in some cases, Game Mode would move all non-game processes onto the first 1/4 of the CPU, but fail to move the game process
off it, which led to core 0 being overloaded unless you manually moved the game process yourself (or used a tool like Process Lasso).
I think with bit of tweaking what it did, such as keeping core 0 reserved exclusively for system processes (which is arguably something that Windows should already be doing) rather than moving non-game applications onto it, Game Mode would have been a feature that most people would have used - especially on higher core-count CPUs.
But that idea has been abandoned now, and pretty much the only thing that Game Mode does is silence your notifications and prevent certain system processes like Windows Update from running in the background while a game is running.
Freesync 2 HDR is the equivalent of G-Sync Ultimate which is largely just a marketing term for G-Sync with HDR support. I don't know if Nvidia puts a requirement to have say FALD for G-Sync Ultimate. FALD has its own issues that won't be solved until we get Mini-LED backlights with a lot more dimming zones or dual layer LCDs which would work closer to how OLED does. Since OLED is not available in desktop size at any reasonable cost it's not much of an option unless you can mount a big TV far away from you.
I believe G-Sync ultimate has strict requirements for things like high-density local dimming (512 zones on a monitor-sized display is a huge amount) and HDR capabilities, while FreeSync 2 only covers things like requiring low frame rate compensation and HDR; but far less strict on the HDR experience.
LG are supposed to be releasing 48" OLEDs next year which would be suitable as a large monitor (assuming you're willing to risk burn-in). The ideal would be 46" since that is 96 PPI (Windows is based around 96 DPI) but 48" 4K would still be 92 PPI and suitable for use as a giant monitor at 100% scale.
