problem with amd readeon r7 m260

Hi, my AMD readeon r7 m260 sometimes is not running how it should run. Ussaly i play CS:GO so i will compare my FPS with this game. When all works completly fine ussaly i have 70-100 FPS . But sometimes what is my problem my game is running with 15-25 FPS and i have observed it happens after i put my computer to sleep. It happens every time. And i dont really know why this happens and what is wrong. On my computer i have 2 video cards 1.st integrated video card - Intel HD Graph family and how u already know ssecond is amd readeon r7 m260. My tought was maybe when i went in cs:go game is running with Intel hd graphics neither with amd r7. but i downloaded MSI Afterburner and check if it's true, but turned out it's false and it runs with amd r7.

So i wonder what is the problem? Sorry if something is wrong with my english grammar, isn't my first language.