my idea.exe.vmoptions seems to be ignored

RP> Is that a correct assumption, am i doing something wrong? Thanks

As far as I know, it's incorrect :)

Java reports as max mem the memory it has used up to now, so it'll only show
512m after using that much mem at least once.

At least that's my experience in seeing the reported mem usage in my app.

The 512 is the max setting with your options. So it will grow to that value if necessary. If you would like the satisfaction of seeing 512 there you can set your min and max setting to 512:-)