Hello CreeperDesu,
Please kindly check the requirement of the games you would like to play.
Your device might not have sufficient equipment or "just enough" to run it.
So if you have install quite a lot of programs or there a some other things running in the background,
it could cause your device to slow down.
Also, in order to let the game run smoothly, fps and the resolution will drop as trade off.
So you may do some adjustment when playing, or try resetting the device,
or consider upgrading some equipment or even .....upgrade to a higher level model....
Thank you.