Sony never commented on how much RAM was being used for the OS/games.
It was mentioned or rumoured that it was 512kb when the console had 4GB RAM and the bump to 8GB made people assume 1GB for the OS.
In any case, I'm a little concerned that both these consoles are due to launch in, if rumours hold, November, and they're still messing around with OS allocations, clockspeeds and whatever else. Nice they're trying to squeeze as much as they can out of final hardware but, hell, it's making me nervous.
Sony and MS were "messing around" with PS3/360 RAM allocation numbers for years past the console launches, streamlining functionality and decreasing the size of the OS footprints to make more room for games. There's nothing weird and worrisome about it, that's just how things work in an age of firmware and operating system updates on game consoles.
I'd be more concerned if they just took a "good enough" stance a year ahead of time and let everything ride.