Dell G7 17 7700 Performance issues

Ok I bought this laptop a month ago, from the first day I had problems with the performance of the laptop so I looked for a solution since I like to solve the problems by myself since it is all faster. The problem was that I did not find a solution since my pc does not seem to have overheating problems or drivers simply and erratically it blocks the video card at 300mhz for the core and 400mhz for the memory, without any previous indication I tried installing the latest bios and nothing and I have not given myself the courage to open the laptop since that would leave me without guarantee. Any solution from someone?