It bothers me how little people care about responsive UI. I haven't used a PS4 yet, so this is more just a general comment than a criticism of the decision - but the PS3 is a bit of a clunker in its cross-media bar. There are spinning placeholders for a couple of seconds every time the icons load. It doesn't exactly scream raw power - why aren't devs embarrassed by these things?
FWIW, Ars' follow-up review of the PS4 talks about how there's still loading indicators in the main menu UI's, which should not happen IMO when you're essentially talking about icons and you have 8GB of RAM to work with.
The issue with the PS3's UI is that it's seen a marked increase in complexity since the initial release, coupled with less resource access. As it stands the PS3's XMB has access to about 80mb of RAM, the rest is reserved for games. Also everything I've heard about the PS4 makes it sound like the UI is incredibly fast and responsive.
He's right, though. On the PS4 desktop, you're not having 10s of thousands of particles that interact with each other being rendered at 60fps. You're not going through 100 passes with different shaders making the perfect experience.
You're having maybe 1000 particles or a 50,000 polygons. Much lighter weight. It doesn't /need/ the performance that a game does.
When the PS3 isn't running anything, the icons don't spin or need to load in. When in a game or app, however, they do. Why? Because the majority of CPU and memory is reserved by the game; the icons will not be in memory; you have to async load them and the game might be using some streaming resources.
