It will never make changes as greater as 20% in the most extreme cases. Those tend to be just pre-configured to maximize such gaming performance, often at the cost of security, compatibility and stability.
Most of those stuff could be adapted to other distros, and tend to be actually. If a change or piece of software made such important benefit to playing games, without any huge drawbacks, be sure it will surely be soon integrated in other distributions.
It will never make changes as greater as 20% in the most extreme cases. Those tend to be just pre-configured to maximize such gaming performance, often at the cost of security, compatibility and stability. Most of those stuff could be adapted to other distros, and tend to be actually. If a change or piece of software made such important benefit to playing games, without any huge drawbacks, be sure it will surely be soon integrated in other distributions.