This is all fun to discuss, and I am certainly no expert, but I will parrot what will be said when the forum mods come in:
- You cannot compare consoles to Windows PC's.
- Laws of diminishing returns are in effect, even if you you could. The same 7990 with 6gb of vram is not meant for 1080p, but multi-monitor. Heck, crossfire is not really meant for 1080p. Take an old 5870 with 1gb of vram, and you will still get great results at a true 720p. Making the jump to 1080p takes, for some games, more than a 5870, with more memory.
- If you increase the target resolution, you dramatically increase the required resources.
- Speaking of which, the vast majority of PS360 games are not 720p, but lower rez and upscaled.
- The Wii U currently has 1 Gig for games, the HD Twins have 512mb for EVERYTHING. PS3 even has split pools. That is 4x the ram for a target rez of 720p (true 720p).
Now, let's look at the ram and specs for the PS4 exclusively for games (from what I have read on the netz, don't crucify me if this is off with ram and core usage).
7 gigs available, 6 cores @ 1.6ghz based off of a bulldozer (Trinity based?) mobile variant, and a custom AMD GCN chip, supposedly on par with a 7850.
So, 1 gig and 2 cores are available for the OS.
Now, knowing that we need vram, and a good bit of it for 1080p + (don't get your hopes up for resolutions higher than that, think of 4k as this gens 1080p), you can factor in as much as required for devs to get wherever they are going outside of a Windows environment.
You guys really only need to look at Watchdogs, and its' graphical downgrades to sort of see what to expect. Then factor in the state of Wii U dev tools at launch. Think NFSMW U, X, Mario Kart, and the other upcoming games to see that the gap will be close enough, as long as the Wii U starts selling and software goes with it.
I still say get both;). Stay away from the VCR though. Even if it tells you it has changed its quality to reflect Betamax standards, it has still revealed the true integrity of the medium:P
I welcome corrections.