crossfire is supposed to be the response to sli because it can hold different x800 cards...but i read the review from toms or anandtech. it said that if u use a x800 pro and an (for example) x850xtpe as the crossfire edition, it lowers its pipelines down to 12 like the pro. so if i bought say an x850xtpe and i wanted to put an r520 in later, would the r520 slow down to the x800xtpe?