Have you checked your task manager? Considering how many chrome tabs you have open, it is more likely that your notebook simply couldn't keep up with the workload. You also have to consider the fact that notebooks are horrible in terms of gaming, and judging from windows 7 it's probably an old one too.

All in all what I'm trying to say is, it's most likely not Toribash's poor optimisation as much as your outdated system.