iPhone 6s lagging

iPhone 6s lag if the temperature is warm or in the case of installing the charger. I get the AnTuTu score of only 47K to 80K if the iPhone is warm or in the charger. how to fix it? I can not play heavy games if while in the charger. this happens in ios my 11.3 beta 6 . What should I do?

Mmm my iPhone 6s Plus is running just as smooth

try to play the heavy game. or try it with 4 test times in antutu. performance will drop.

iPhone 6s lagging
 
 
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