Which process eats so much memory, the IDE or ppc386 ?
1. using lazarus IDE on windows is an own process, and so is the compiler (ppc386 or ppcx64)
2. the compiler uses the internal linker, which typically doesn't use more than 250MB. The high memory values (1GB+) are for external linking, not internal, which is not default on Windows.
Temporarily disabiling smartscreen and/or window defender and other security software might rule out those as problem source.