I have 80+ mods installed in Minecraft 1.5.2, Forge version 5.2.23.738. I can play Minecraft perfectly fine in 32 bit but I'm unhappy with the performance drop of using 32. But when I try to play it in 64 bit I get out of memory prem space errors. What happens is the Mojang screen will be showing and the game is loading, then it will go black screen. I check the forge log and this is what I have.

 

 

2013-07-08 19:18:29 [iNFO] [sTDERR] Exception in thread "Minecraft main thread" java.lang.OutOfMemoryError: PermGen space

2013-07-08 19:18:29 [iNFO] [sTDERR] at sun.reflect.GeneratedMethodAccessor3.invoke(Unknown Source)

2013-07-08 19:18:29 [iNFO] [sTDERR] at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)

2013-07-08 19:18:29 [iNFO] [sTDERR] at java.lang.reflect.Method.invoke(Unknown Source)

2013-07-08 19:18:29 [iNFO] [sTDERR] at com.google.common.eventbus.EventHandler.handleEvent(EventHandler.java:74)

2013-07-08 19:18:29 [iNFO] [sTDERR] at com.google.common.eventbus.SynchronizedEventHandler.handleEvent(SynchronizedEventHandler.java:45)

2013-07-08 19:18:29 [iNFO] [sTDERR] at com.google.common.eventbus.EventBus.dispatch(EventBus.java:314)

2013-07-08 19:18:29 [iNFO] [sTDERR] at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:296)

2013-07-08 19:18:29 [iNFO] [sTDERR] at com.google.common.eventbus.EventBus.post(EventBus.java:267)

2013-07-08 19:18:29 [iNFO] [sTDERR] at cpw.mods.fml.common.LoadController.sendEventToModContainer(LoadController.java:192)

2013-07-08 19:18:29 [iNFO] [sTDERR] at cpw.mods.fml.common.LoadController.propogateStateMessage(LoadController.java:172)

2013-07-08 19:18:29 [iNFO] [sTDERR] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

2013-07-08 19:18:29 [iNFO] [sTDERR] at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)

2013-07-08 19:18:29 [iNFO] [sTDERR] at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)

2013-07-08 19:18:29 [iNFO] [sTDERR] at java.lang.reflect.Method.invoke(Unknown Source)

2013-07-08 19:18:29 [iNFO] [sTDERR] at com.google.common.eventbus.EventHandler.handleEvent(EventHandler.java:74)

2013-07-08 19:18:29 [iNFO] [sTDERR] at com.google.common.eventbus.SynchronizedEventHandler.handleEvent(SynchronizedEventHandler.java:45)

2013-07-08 19:18:29 [iNFO] [sTDERR] at com.google.common.eventbus.EventBus.dispatch(EventBus.java:314)

2013-07-08 19:18:29 [iNFO] [sTDERR] at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:296)

2013-07-08 19:18:29 [iNFO] [sTDERR] at com.google.common.eventbus.EventBus.post(EventBus.java:267)

2013-07-08 19:18:29 [iNFO] [sTDERR] at cpw.mods.fml.common.LoadController.distributeStateMessage(LoadController.java:103)

2013-07-08 19:18:29 [iNFO] [sTDERR] at cpw.mods.fml.common.Loader.initializeMods(Loader.java:691)

2013-07-08 19:18:29 [iNFO] [sTDERR] at cpw.mods.fml.client.FMLClientHandler.finishMinecraftLoading(FMLClientHandler.java:213)

2013-07-08 19:18:29 [iNFO] [sTDERR] at net.minecraft.client.Minecraft.func_71384_a(Minecraft.java:448)

2013-07-08 19:18:29 [iNFO] [sTDERR] at net.minecraft.client.MinecraftAppletImpl.func_71384_a(SourceFile:56)

2013-07-08 19:18:29 [iNFO] [sTDERR] at net.minecraft.client.Minecraft.run(Minecraft.java:733)

2013-07-08 19:18:29 [iNFO] [sTDERR] at java.lang.Thread.run(Unknown Source)

 

Might I add, Java 1.7.0_25 with -Xmx2048M -Xms2048M -XX:PermSize=256m -XX:MaxPermSize=512m. Also the server I created for these mods work perfect on 64 bit.

-XX:PermSize=256m -XX:MaxPermSize=512m

Different values are not recommented, because if the PermGen has reached the min value, it has to reallocate it. Use a fixed value:

-XX:PermSize=512m -XX:MaxPermSize=512m