> I wish the graphic driver could be better as playing Youtube videos constantly crashes Firefox on Ubuntu

Do you have the xf86-video-intel driver installed? Try removing that package and just relying on the kernel modesetting DRI driver instead. That's been the recommended way to run Intel graphics for long time now.

I don't know if that's your issue, but it this caused a lot of weird issues on my x270 with Firefox.

Get the oibaf PPA and dist-upgrade.