Sweet little world enrico,
Your materials and textures are always great.
Looks like a 1792mb or 2gb gpu are the ones to go for 'artiste' grade stuff.
The extra space would allow a full compliment of maps, some more polys, bigger render size...
As you have shown though you can do quite a lot with 896mb.
I agree with the other commentators, at 20-40s/ frame I think we need to see an animation soon.