On-board gpu and seperate gpu

Your onboard GPU wouldnt help the 220 out at all so its not supported, you could use it to drive another monitor if you wanted but you cant have them work together in SLI. ATI has hybrid crossfire but its only supported with the very low end GPUs like the older 2xxx and low end 3xxx cards.

what about putting the geforce 220 in sli with a geforce 9400??

not possible.. gpu has to be identical

besides the not possible, the 6100 is so slow that even if there is a GPU to use, it wouldn't be worth it (even if it worked with newer ones, it would add anything, its just too slow)

OK thanks a bunch guys.