I had the same issue with my Samsung s6
Look at this fix from the user ARTIC ICEZ
GUYS I MAY HAVE FOUND A SOLUTION! (Note : This has a potential chance of bot working or everyone.
Step 1 : Open Settings and go to" Application" then "Application Manager", or find any way to get to where app data and cache etc... can be wiped or uninstalled.
Step 2: Scroll down and find "Game Optimization Service" and Click Uninstall/Disable.
Step 3 : Power off your device and take it off charge if you have it plugged in.
Step 4 : Enter the "Android Syterm Recovery" by holding down the volume up button, home button, and power button at the same exact time when the the device is powered off. (Note : Different devices may have different ways of entering the System Recovery Menu, so please Google, "How to enter Android System Recovery on the <Phone Name>"
Step 5: Navigate through the menu using the volume +/- (Up/Down) keys. Go to "Wipe Cache Partition" and select it using the Power Button. It will promt asking if you want to do it, click "Yes" (Do not worry this does NOT clear any system data).
Step 6 : After clearing the cache you will be put to the home menu of the Android System Recovery. Navigate your way to "Reboot System" and confirm using the power Button. Once done your phone will boot up as normal and all of your damaged applications should be restored.
I have tried this and my apps have shown no sign of it's usual ways over the course of 6 hours, which is a large improvement over the 5 minutes that it used to be. If you have questions you can always ask and I really hope this works for everyone here. Thank you! (Sorry for any typos that I may have made.)
Post Link:
https://forums.androidcentral.com/s...i-fix-screen-pixels-blurry-when-gaming-2.html
A recommendation BLOCK THE UPDATES IN GOOGLE PLAY, because everything will comeback to be pixeled when the Game Optimization Service get the update again :-/. I did that and it's been 12hours without a problem