Hello! I'm running Win 7 64 bit in Parallels Desktop 5 on a new 27 inch iMac with i5 CPU and ATI HD 4850 graphics, Mac OS 10.6.3, latest PD 5. I use some applications like CATIA, 3ds max and I get choppy graphics. What I mean is that when I rotate the model I can see that the frame rate is not constant... there are constant pulses. Slow Slow Faster Slow Slow Faster.....strange The second thing is why there is a limit of 256 mb of video ram when my graphics card has 512 mb? BW