Make sure you have all system drivers, Chipset, GPU drivers up to date. Make sure windows is up to date.
It could be that your temps are high causing your CPU to throttle. So you can use something like HWMon/Info to monitor that and be certain. It 's worth checking the vents on the laptop to be sure they are dust free. It might even be worth taking the cover off, and making sure there is no dust accumulating, if there is, clear it with some compressed air.
What model is your laptop? We can look at the specs in more detail. What resolution is the screen?
Your specs are pretty decent, so you should be able to play games fine at 1080p/60hz without having to restart your laptop each time.