I Just did a clean install of Forge and i have no other mods installed for Minecraft.
The install i did for Forge was forge-1.6.4-9.11.1.965.
My JVM argument is only allowing 1G instead of anything higher.
I have Tried -Xms1536 -Xmx1536 -XX:permSize=512m -XX:+UseParNewGC...