Autodesk Inventor is known to be touchy to the quality of the graphics cards. It squeezes the performance of graphics cards to the limit and uses them differently than usual 3D applications the cards are made (optimized and benchmarked) for – computer games.
From my experience I will recommend to always pick a card from the Autodesk Inventor compatibility list for your Inventor workstation. Otherwise you will probably get failures, strange display artefacts, misplaced drawing texts and other problems running Inventor.
But it is not only the card type and model but also and even more important – its driver version. Autodesk always certifies a specific combination of graphics card – driver version – Inventor version. So you’d better to stick with this combination. Card manufacturers usually release driver updates. But not always newer means better.
We are using nVidia cards in all workstations. Recently, nVidia has released a new driver update (91.85) which should fix memory leak problems in OpenGL applications. This seems to be an important update but I will rather wait for Autodesk to certify this driver version for my Inventor 2008.