Does windows desktop basic themes really spend less memory?

Hi, I have an old notebook and I’ve upgraded it from XP to 7;Its a really tough buddy and Im very happy with him (you know, after almost 8 years…) but win7 display eats a lot of memory, and, as I used to do with XP, I simplyfied the display by discarding shadows, animations, etc, and I did the same to win7 now. But that makes me wonder, does the basic windows theme really eases the load on memory?