Still no go... back to 3GB RAM

After installing Vista Service Pack 1 things seemed to be running pretty well.  Both ATI cards were functioning and looking good.  But after a couple hours of use, system performance degraded, especially relating to video.  Then the ATI drivers crashed and restarted successfully, just like the nVidia drivers did.

So, back to 3GB RAM.  I will submit a ticket to Microsoft when I have the energy.  Otherwise, I am considering this case closed.  I cannot use 4GB RAM and 2 video cards on this Dell OptiPlex with Vista 64-bit.