Pixelmon Mod

i just downloaded pixelmon 4.2.5 or 3 not sure but it requires minecraft 1.8.9 and thats the forge im using but it will be loading and it gets to a point and just freezes and when i try to get out on minecraft it says that it crashed how do i fix

Some Body wrote:http://pixelmonmod.com/wiki/index.php?title=Frequently_asked_questions#Minecraft_never_finishes_loading.2FMinecraft_is_very_laggy_after_installing_Pixelmon.21_Can_I_fix_this.3F

I did red somewhere that it's a memory issue. I'm assuming this changes memory from 1g to 2g?

Yes.