I implemented a system recently that is a drop in replacement for a component of ours, old used 250gb of memory, new one uses 6gb, exact same from the outside.

Bad code is bad code, poor choices are poor choices — but I think it’s often times pretty fair to judge things harshly on resource usage sometimes.

Sure, but if you’re talking about 250GB of memory then you’re clearly discussing edge cases vs normal software running on an average persons computer. ;)