(0,1) (2,3) Is what i've gone with.
With folding, i just let it run all 4 cores... I seen no noticable ppd change, and keeps the cores an even temp. I use to run it 1,2 and had 10-15C core differences.
Just watch, as windows auto places gpu on 3.
Oh, watch your OC, foldings very hard on them.