ACAD 2008 has trouble with later graphics card

I use Autocad 2008 for all my needs, even 3D solids modeling work. My computer is an HP Compaq dc6700 convertible desktop running Windows 7, 32bit with 4GB of RAM. While working on a large 3D model the rotation and other graphics was getting too slow so I decided to buy a new graphics/video card. It is an AMD hd 6670 Series Graphics Accelerator card with 2GB of its own RAM.

It really is an improvement over the older Asus card in most cases, but when I loaded Autocad I got a message that listed the graphics card it found and said that it is not certified. No surprise, as the 2008 software couldn't know about a later piece of hardware.

When I tried to load the large 3D model it took a VERY long time and then it wouldn't rotate at all. It tried for several minutes then just halted. I went to the Autodesk site for the certified graphics card and, of course, this one wasn't there. My question is this: How can I make this work better and faster with the newer card. I can switch it back to the older card but I prefer not to and I really don't want to buy another card.

What do you suggest?

Is hardware acceleration enabled or disabled? No matter which one it is try the opposite and see what happens.

4GB RAM? Are you utilizing the 3GB Switch in your boot.ini file?

My question is this: How can I make this work better and faster with the newer card. I can switch it back to the older card but I prefer not to and I really don't want to buy another card.

What do you suggest?

@frankreid - Im not familiar with your PC but as always recommended we need to meet the minimum system requirements set by the software company. I just search on Google and I found this interesting info about How a computer will interact with 3D. .Check this link maybe this can help you (I think an upgrade can help but still, its up to you,I hope the link will atleast give you an idea) http://blog.grabcad.com/2011/07/how-to-build-a-faster-3d-cad-pc/

regards