[WindowsCentral.com]

Game Mode is a new feature in the Windows 10 Creators Update, and it's designed to focus your system's resources and boost the quality of games.
By limiting background tasks, Game Mode seeks to increase the smoothness of games running on Windows 10, redirecting your system towards the game when it is activated. Microsoft stated that the feature would have modest improvements for Win32 titles, due to the non-standardized environment. But the Universal Windows Platform (UWP) games typical of the Windows 10 Store should see immediate benefits.
I was curious as to what (if any) real-world benefits Game Mode would have for multitasking on my devices, and I came away with some mixed results. Keep reading for specifics.

Full story from the WindowsCentral blog...

[Josiah23]

Without reading the full story from the homepage

I seen a video on this from LinuxTechTips and Game mode made very little to no difference and in some cases slight worse performance, and it was tested on 3 different type of systems (budget, mid, and high end gaming setups)

I think Game Mode is more-so for computers that normally have slight trouble or are experiencing significant spikes and frame rate drops while running games.

I had Game Mode on since installing the Creators Update for W10 and I haven't noticed much improvement (probably because I already have a high end gaming PC and don't experience any frame drips)