Quote - I have Radeon cards on my laptops, and Poser has always hated those. Now, my main laptop is absolutely capable of running Poser, memory and processor-wise, but that ATI card.. just doesn't work properly. I have to switch to sreed on those. My main computer has an NVidia card, which Poser seems to prefer.

I know that doesn't help much, but switching to SreeD may be your option here. 

It's not just Poser, it's ATI and OpenGL in general.
ATI cards are far more suited for games, and have pretty weak OpenGL support all around. Aside from their FireGL cards, which are their equivalent to Nvidia's Quadro line.
But you can find the same ATI complaints from people using them for all sorts of OpenGL programs.
Simply put, the ATI's are more for gaming and DirectDraw (DirectX), while Nvidia has far better support for OpenGL (as well as DX...)