Lag spikes when using Chrome Youtube

Hello guys,

It's me again, and this time there is an annoying problem while using Adobe Flash Player on Youtube. If I am playing a video (720p or 1080p) on Youtube and loading a new webpage/tab at the same time, the video player starts to lag (not video connection lag). If I play 2 videos on Youtube at the same time, both video players lag, and sometimes this causes un-responsiveness of Chrome and can possibly lead to crashes.

I know my laptop is low-ended but that shouldn't happen since I can play videos rather smoothly on IE and Firefox, even though I open new webpages and playing 2 and more videos at the same time with the same browsers.