I have a feeling that what is happening is that the processor is getting hot - too hot - and performance is being throttled as a result. Your laptop is 5 years old. It is reaching the point where thermal dissipation is starting to degrade and higher temperatures are the result. What I think is happening is the thermal interface material (TIM; the paste that transfers heat from the processor to the heatsink) is drying out or breaking down (separating) or perhaps both. If this is the case, you need to have the TIM replaced. Before doing so, I suggest that you run an application - AIDA64, HWMonitor, SpeedFan, etc. - that will allow you to see what is happening to the processor temperature. If it is indeed overheating and reaching the throttling point, replace the TIM. Now, this can be an involved process and may not be something you want to tackle yourself. Most PC repair shops will do this for a nominal fee. If this is indeed the problem, replacing the TIM will add years to the lifetime of the laptop.
Hope this helps,
antes e apos o jogo , bom eu troquei a pasta térmica para Pasta Térmica Cooler Master Master Gel Maker , mas eu não troquei o dissipador vou verifica e trocar dissipador do computador , eu não sei a temperatura máxima ou normal do notebook , eu uso mesa de cooler de notebook no máximo nível 6 da multilaser.