As long as the processor is dual core, and has decent ram, there shouldn't be any slow down. H3ll, i run 4 of them and have no slow down. Now one thing I did notice, is that CF 3.5 runs super super fast on my setup. When I use OM though, the response is very slow. Which may be the OpenGL thing that your mentioning. Even if I turn off enhanced graphics in OM, its still sluggish.
Yeah sounds like OM is running in software mode, could you post (or pm) your debug file. That should tell us if OM is running in software mode or not.