This is difficult to diagnose as there could be many possible causes. I personally had some problems awhile back due to a nvidia driver that has since been patched. I noticed your post is a bit older so I am curious if the driver update helped you as well? I often run a program by NZXT called CAM it is free for all and works very well, it will allow you to monitor the load on your cpu, graphics card, ram, and temps for all of those devices. Laptops tend to run warm and this can cause thermal throttling which would greatly reduce your frames per second. I would recommend downloading CAM or a comparable software and see what the system temps are. If your temps are the problem you can try getting a laptop cooler which is basically fans that your laptop sit on. If you notice that the load on your graphics card, ram, or cpu are maxed that is likely the problem. In that case you want to close any programs or background processes that you can before playing. That should help. If you continue to have these problems respond back with the load levels, fps, and temps of your components and I'll try to help as best as possible. Also if temps are running high I would be cautious about overclocking as that can add quiet a bit of heat.
This is a link to the NXZT software that I use for monitoring. Feel free to use something different though.
https://www.nzxt.com/camapp