W7 has mm algorithms something similar to os x.8 or at least for what I've seen. I am baffled as to what gave you the impression that os x mm is much better than that of w7 but if you're referring to mac using the concept of inactive memory, w7 has a parallel concept called superfetch aka standby memory. It's been around since vista days and works similar to inactive memory from mac by caching recently used programs. The difference appears to be w7 caches programs into standby memory immediately upon startup whereas os x does not. Os x incrementally increases inactive memory as you use programs but does not load anything into inactive upon startup. Start your task manager > performance > resource monitor... and you will see how much w7 uses as standby memory. W7's task manager only shows the "wired", "active" memory as solid greens.
Like I said, my one gripe w/ os x is its mm in it being the active memory gradually increasing over time to the point where the os completely exhausts all of physical memory and being forced to use your phyiscal storage disk as a temporary ram called page out for mac and pagefile.sys in w7. For os x, it appears that the threshold point at which os takes aim to reduce active or inactive memory is when it
has to resort to hdd/ssd.
You might have noticed some slight stutter in gui animations or a slight lag b/w the time you clicked on an app and the time it took to actually open when this kicks in. W7 does not work like this - at any given point of time, it will always allocate a certain amount of ram bounded by the maximum physical ram size dedicated to free regardless of how many programs have been run in the past. Due to this difference, it will very rarely have occassions when it has to resort to pagefile to act as a temporary ram. This case arises rarely but I have seen it happen when there are apps that give rise to spikes in memory consumption like hfss which I had to use extensively during my postgraduate days. It was such a memory hog that even our server-graded computer that had 128gb ram was paging out.
Just b/c someone said it's better doesn't mean it's better. I've learned to be careful what I say and what I read on the net as it is just as easy just to google stuff and read about it and pretend I am qualified to comment on this kind of matter as someone learns to do simple arithmatics and claims I know how to do triple integrations.
I'm no software engineer so all of this is mere a conjecture but I know people who work in this kind of industries for some of the biggest companies in the world (microsoft included obviously) so I have some interesting discussions about things like this every once in a while.
If you wanna get some more insight into some of the basic concepts of mm in w7, I will post a link for your perusal:
http://support.microsoft.com/kb/2160852