Can't allocate more than 1gb memory, and no options to select 64-bit Jjava

[Fence]

I just got a new pc, and I've tried launching a modpack, and it would just not work, because I don't have enough memory. But when I try allocating more memory, it doesn't let me do more than 1gb. I also do not have the option to select anything other than 32-bit versions of Java, even after (I think successfully) installing 64-bit Java.

[ZanyScum]

Try

java -version

to know which version is being executed when "java" is called. Then - probably - uninstall the ones you don't want and try 'java -version' again.

Either your newly installed version is the wrong one or it is hidden by an older version. Uninstalling the older version might be enough. If you WANT/NEED to keep the older version, you'll have to change the path order.

In the worst case, uninstall ALL java version, make sure "java" on the console does nothing, then install the 64-bit version.