So, I'm running a C2Dual 2.0ghz macbook with 4gb ram installed. Yet, when I try to watch a video (non-hd) on vlc player, while running firefox, the video stalls. Activity monitor says I have over 70% cpu free with 400mb ram free with 1.4gb inactive. What is happening and why? PS. I have recently wiped my drive did a fresh os x install, and everything is updated.