Originally Posted by Jan Kyster

It's a misunderstanding that an efficient system leaves free RAM. After all RAM is the most efficient place to store and handle data, so part of Win7 being as efficient as it is, is it's way of using all available resources in the best possible way.

I've installed many machines with the MS recommended 4 GB and it's perfectly fine. I doubt there are any games that wouldn't run well on a Win7 with "only" 4GBs

But agreed, 6 GB is really, really good. And cheap nowadays...