PS4 OS is rumoured to take 1GB, so it'll be 7GB for games....personally I see the PS4 OS taking 2GB ram, then over time Sony can releasing ram just like they've done with the PS3.

A fair chunk of the xbox' spec is still publically unkown. Such as the architecture and performance of the custom blitters and ESRAM. The xbox also seems to offload a fair chunk of OS function to the ARM subsystem. I thought the PS4 was rumoured to have an ARM subsystem as well, but I've read rumours on Digital Foundry that there are actual main CPU cores allocated for OS.

So the proof will be in the pudding, as they say. But the xbox appears to be no slouch if E3 demos are anything to go by.

It's all about games.. I don't mind if the X1 or PS4 have better performance, as long as we have nice IPs from both sides.
Plus, I don't understand why do you care about performances, since it's up to developpers wether to use the full power or not.

Early gen you wont see much of a gap, but late gen when the consoles start to look a bit dated that's when you will notice the difference between the two consoles.

Still the games have not ran on the actual hardware for both Xbox and PS4, and those games shown aren't finished yet where xbox games are said to be running on dev kits with Nvidia GPU so we still dont know about bone power by running a game. Lets wait and see the games running in real hardware when games released.

I believe PS4 version of Multiplatform will have higher texture and good framerate than Xboone, and PS4 games will be best Looking games becoz ND, GG, MM, and QD of Sony can unleash the PS4 potential to max and also they are best developers out there who proved with their games.

This. People seem to forget that PS4 arhictecture also has lot of improvements over off the shelf parts.

For all those who missed Gamasutra interview with Mark Cerny, here it is again:

http://www.gamasutra.com/view/feature/191007/

The difference could end up to be the same game running in 1080P on PS4 and in 720P or something like 1280x1080 on the Xone. That is a pretty important difference, especially if you own a full-hd LCD tv.

Forza 5 uses prebaked lighting vs DriveClub's dynamic lighting. Not saying it doesn't looks better (it sure does), I'm just telling you the biggest reason it looks so amazing.

The sun moving across the sky, varying clouds blocking the sun, all of that updating what you see in real time, dynamic weather effects, rain, snow... DriveClub does so much more. Each track will look different every time you drive on it and will change it's appearance as you drive. Tracks in Forza 5 will always look the same.

The DriveClub build they've shown was 35% complete too.

This time there will be a bigger diffrence. PS4 has the faster and better ram. Will have a smaller and lighter OS footprint allowing at least an extra 1gb of ram over X1. The GPU has 18 compute units instead of 12.  So the PS4 will have a an at least 30% advantage but that will increase when developers start truly leveraging the machines power.  As for the PS4 games shown at E3 they were all running on PS4 hardware unlike some on X1 were probably the PC versions. The Only X1 game that impressed was Forza 5. Drive Club was an early build. I think they deliberately showed a pre alpha 35% one. There is no way they can only be at 35% complete with about 4 months of development left. They probably holding back a later build for Gamescom and other titles for TGS

pretty clear that games on PS4 will always have the better framerate for games that are not locked at 60 frames on both platforms. Simple as that all day long.