Many thanks to the three of you.
Relieved to know that ProRes clips go right into Premiere Pro (so long as FCP is installed on the computer). Sounds like there is indeed much more real time capability with effects on Premiere than FCP, I suppose due to the use of the graphics card.
I read a couple reviews on the Matrox RT.X2, but I need to look at it more to understand exactly what it does.