TSE - ATI vs. nVidia

Hi all..
Yeah, we all know that lighting and materials are still "under construction" in TSE.. but...
recently I've discovered the following:
The shadows/lights/materials are giving different results on different video cards.
In the following screens used the same: scene, textures, materials.cs, DIFs, TSE build.

I've installed on my computer one by one cards: ATI Radeon 9600Pro, nVidia 6800GT, 660GT, 5200, 5600.
Used different video drivers - latest & previous official, OmegaDrivers (prev & latest).
The drivers didn't give any difference, looks like it's only "brand" - ATI vs. nVidia
And more: when in editor (F11) with nVidia cards world looks different when in game. but ATI is okay.
So, here comes the results...
ATI Video Card, IN GAME:
ATI Video Card, IN EDITOR:
nVidia Card, IN GAME:
nVidia Card, IN EDITOR:

Tomorrow I'll try to find some different ATI cards to make additional tests.

P.S. And as addition: try to find difference (clean TSE Demo):
ATI Demo shoot 1 vs. nVidia Demo shoot 1
See the shadows and
ATI Demo shoot 2 vs. nVidia Demo shoot 2
pay attention to stairs textures.