Not sure, since the base card should have quickdraw acceleration anyway I think. Also I don't think the DSPs can do photoshop and quickdraw at the same time (guess that does not matter since the App pretty much locks the system when you are doing DSP work).

I you look at the Thunder II Supermac line the differences between the 3 top models is DSP card addon , RAM onboard, and for the high end one a different monitor connector.