I'm sorry but low RAM usage is not good performance, those are not the same.
Also, I've read somewhere that all memory not in use is wasted memory. I find that thought really interesting. If an operating system would be able to always maximize RAM usage by loading every peace of software and information it uses or is about to use without using swap or a pagefile it shoud be more responsive I think.
Would you mind explaining how wishlisting a game helps the devs? Is it an algorithm thing? Will it be shown to more people when it is being wishlisted more?