F@H uses almost no graphic resources, even though it runs a GUI. On my system I run a console version (no graphics to see at all) and a special beta for my ATI video card. Booth run together just fine. My ATI peaks at 90% usage of it pixel shaders and my CPU runs at 30% for ATI support and 70% for the console edition.
Yep, 100% CPU utilization, pretty much 24/7. I FReep, build presentations and databases and download videos.
What I cannot do, courtesy of M$ OpenGL, is run a program that requires any OpenGL support. M$ wrote it so that only one program can manipulate its threads at a time.
I do run Visio on occasion and have never noticed a problem. I also run Voloview but only to support a customer.
I close my GUI to run one older game, since I know that it uses OpenGL. I never close the console version.
If you are running at “only” 40% then you are only processing on one core of your dual core chip. I have a dual core system that I keep two console versions running at 100% each, one on each core. I get lotsa points for that one.
Hitting 40% isn’t a problem; that is F@H running just fine. We may need to tweak you system to get rid of the CAD conflict. As important as F@H is, it does take a backseat to making a living and playing games.