A common question amongst Minecrafters is if they should run 64 bit Java or 32 bit Java. The short answer is that you should run 64 bit Java whenever possible. This is because of a number of reasons. Running a 32 bit version of Java limits you to only be able to use a maximum of 4 GB of memory and runs slower which is especially noticeable when rendering the world in Minecraft. 64 bit Java on the other hand allows you to access 17.2 billion GB of memory so Java won't hinder your ability to use super RAM intensive programs such as an instance of heavily modded Minecraft. Although 64 bit computers running 64 bit operating systems can run 32 bit applications, 32 bit computers can not run 64 bit applications.
