Improving Endless Mission Performance

[Leadpaintchips]

(Just a warning, I'm just computer savvy enough to break it hard, so keep it simple for me guys!)

 

Ok, so I've been having this issue for a while, after about 25 minutes, or 25 waves on a Void Endless mission (survival or defense), I start to have some serious issues with stuttering and some serious lag issues.  I'm playing on a Lenovo y510p laptop (which has Intel i7-4700MQ CPU, and a GeForce GT 755M GPU  With 8GB Ram).  If I use the Nividia recommended settings, It cranks it all up to high.  Was wondering if there was anything that I could do in order to make it so that I can actually do something in the later waves, instead of just seeing everyone jump everywhere.