It's worth noting as well that if this truly is what Microsoft has planned, and it's well received by consumers, Sony has no way of emulating it completely with the memory setup they have chosen without significantly restricting the amount of RAM available to games.
Next gen is going to be really interesting.
That's kind of the point, isn't it?
I mean, this whole thread is about the "4 GB DDR5 > 8 GB DDR3" thing and the "Orbis GPU > Durango GPU" thing, while ignoring that so far well collaborated rumors point to:
1. The Durango only having 5 GB of DDR3 available for games, while the Orbis will have 3.5 GB of DDR5. That more than cuts MS' quantity advantage in half (from 4 GB to 1.5 GB). 1.5 GB isn't going to mean shit against DDR5.
2. Many rumors have said that the Durango has 2 or 3 cores restricted entirely to the OS, while the Orbis is only supposed to keep one away from developers.
The Orbis wins in a hardware v. hardware match-up. When you factor the performance cost of a large OS that gap only widens.
Sony is betting on hardware and first party/exclusive games. MS is betting on convergent media and 3rd party games being 1. the market leaders and 2. relatively similar across both platforms. It is a legitimate deviation between the two in terms of strategy, even though they're both sourcing much of the silicon from AMD.
The only real wild card in this equation is Sony's scaling OS implementations. They've done some pretty impressive things with the Vita's OS. It runs a very small footprint in-game but thanks to some fancy OS design minimizes games without closing them, greatly reducing their memory consumption and allowing access to other applications and features. Even still, that isn't a totally seamless transition, just a passable facsimile. That might be enough for Sony. It really depends on how big media convergence really is in the next 5-10 years, and that might largely depend on how well MS can market the Xbox 720 along with other Windows 8 devices.