If you have the new sound system, try to get back to the old one. Was having some freezes cause of it...
My guess is a problem with the GPU because according to the benchmark it never even got that close to the stock clock speed. Since you're having frame drops, it's likely that the card is overheating, especially since the R9 200 series cards didn't exactly have the lowest temperatures.
Download MSI Afterburner and use it to monitor the temperature while playing. If it hits 90c, close out of the game and turn the fan all the way up and see if it still hits 90c. If it does, clean out the inside of the case because there is probably some dust blocking the air flow. If that still doesn't work, try replacing the thermal paste in the card.
I also kind of think the same thing is happening to the CPU because it's also not going up to the boost clock it's supposed to have. It is boosting, but only by 200 MHz when it's supposed to boost by 400 MHz.
Its either your mouse or monitor what makes it. you should also change your keyboard might cause the problem but often is the last thing you should do.
Ty man for answering , i have already installed MSI Afterburner , it does never hit 90c , i don't think its a temperature problem.
i didn't really understand what do you exactly mean by boosting to 200MHZ and 400 MHZ!