BEFORE YOU ANSWER
open a command prompt and type or paste the following:
java -versionyou are using 64 bit java IF AND ONLY IF the phrase 64-bit appears.
java version "1.6.0_21" Java(TM) SE Runtime Environment (build 1.6.0_21-b07) Java HotSpot(TM) 64-Bit Server VM (build 17.0-b17, mixed mode)When I run it on my 32 bit laptop, I get instead:
java version "1.6.0_22" Java(TM) SE Runtime Environment (build 1.6.0_22-b04) Java HotSpot(TM) Client VM (build 17.1-b03, mixed mode, sharing)Which version do you use for minecraft? I typically use the 64 bit version whenever possible because the RAM ceiling is higher and Minecraft has ... RAM FATNESS ISSUES. I have only very rarely had issues with the game crashing for any reason apart from something I did to it (like blowing up 12000 blocks of tnt)
That being said, you might see a performance increase if you download minecraft.jar from the site and run it with:
java -Xmx2G -Xms512M -cp Minecraft.jar net.minecraft.LauncherFrameprovided you have the RAM to do so.