The Windows /3GB bootflag might have also given the needed 0.5GB of extra heap space, but apparently the JVMs couldn't really make use of it according to https:

The Windows /3GB bootflag might have also given the needed 0.5GB of extra heap space, but apparently the JVMs couldn't really make use of it according to https://stackoverflow.com/questions/21631167/java-heap-space-and-the-ram https://stackoverflow.com/questions/21631167/java-heap-space...