The devkits for PS4 have only 1.5GB free for VRAM.
http://beyond3d.com/showpost.php?p=1712366&postcount=111
I think the division was...
- 1.5GB for OS (not optimized yet)
- 1.0GB for games (CPU)
- 1.5GB for games (GPU VRAM)
Now with the 8GB kits will be great increase (2GB + 2GB + 4GB? Or 2GB + 6GB dynamic).