autocad 2011 shadow problem

[CAD911]

I created a few primitives on a planar surface turned sunlight on and full shadows. When I change the date or time of the sun I get the object shadows and some weird shadows like if there were clouds in the sky:shock: I have all settings in performance settings under manual tune on except for texture compression. When I render the shadows are correct, but on screen they are not accurate. what could be the problem? By the way in ACAD 2010 all works fine.

 

My system specs are:

Alienware M17X R2

intel i7 820

Ati hd 4870 in cross fire (but autocad does not support this)

4 gigs mem @ 1333

17" RGB LED

Win 7 pro 64 bit

 

Thanks

CAD911

[ReMark]

Can you post a sample image?

[abmw1000]

Have you solved the problem? I had the same problem in autocad architecture 2010 (random shadows from above) but my 3DCONFIG settings had full-shadow display turned OFF. Turning it on fixed that problem. But now when I select Full Shadows it doesn't display the ground shadow component (only the internal shadows). Ground shadows display fine on their own. Any suggestions??