@amigadave

In my honest opinion it is best to just use a single 1.25ghz card and overclock it to 1.5ghz. It is outperforming my 1.75ghz Mac Mini by a good margin for whatever reason. Games like to hiccup on the Mac Mini whereas my Mac MDD runs just great and uses much less CPU usage when I use emulators. Also, temperatures drop drastically with a single core cpu even using an aluminum heatsink. (though I have 3 MDD macs and several CPU cards and two spare logic boards.)