Audio Video Sync issue

I got it to work my hackintosh but when i run basic.sh again it gives a memory error..i changed the basic.sh -m 2G \ to -m 4G \ and it said cannot allocate memory.
Changing it to 3G worked. what is the way to give it maximum memory. and can i run Mac os without
running basic.sh ?

Also, running videos on youtube has audio and video incorrectly synced.

What to do?

thanks