<p></p><p>Wasn't the use of more than 4 gigs of ram the only benefict of a 64bits s.o?</p>
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<p>That's the main benefit. I think this implies that these games simply need a lot of RAM. The real limitation for software is 3GB (and even that is somewhat of a hack, as it's normally 2GB). I find it a little funny because the console versions do with a lot less RAM, and a lot of people complain that PC games are nothing but console conversions.</p>
You can't really compare consoles and PC's in that sense. Consoles manage with less RAM cause every Xbox 360 and Playstation 3 are the same. Developers can optimize games because they know exactly what hardware it's going to run and which software will be running in the background.
However, PC's have a pretty much unlimited number of combinations of hardware and software. You could be running a dual core CPU, a 64-bit OS with 24GB RAM and an overclocked videocard or you could be running a quad core, 32-bit OS, 4GB of ram and a budget/HTPC card.
TL;DR
Consoles have no variables, PC's do.