The main thing making these java arguments require 64 bit are the "-Xms2048m -Xmx2048m" if you lower those numbers it won't require you to use more memory than a 32 bit system can hold. That's the first part of what I said. The next part is a warning not to do that because the entire point of these performance tweaks is to use a bunch of ram to offload some of the performance problems in modded Minecraft. Ram that you won't be able to use at all in a 32-bit system. And as far as I'm aware, the packs DO run just fine on 32 bit systems. The packs don't use these performance tweaks. These are special/separate/unofficial and you have to add them yourself. I'm sure if you go here: http://support.feed-the-beast.com/ and aska question, you should get help and could probably run Monster or DW20. If not, there are mods that can easily be removed from them to give you nearly the same experience without killing your computer. Or the FTBLite pack (they still have that, right? I haven't booted up the FTB launcher in ages. I play my own self-assembled modpack). Some people can't play "all the mods" at once, which just sucks; but a smaller modpack isn't all that bad. It's tough to experience all the content of something like Monster!