shooting RAW + Jpeg

had lots of opportunity to figure this out
but for some reason never did
if i shoot RAW and jpeg fine on a d2x does it slow down the capacity to write images to the buffer then on the card
if so by how much, does it slow down the wite speed significantly?
in jpeg mode fine i can get at least 10 shots in burst mode on the d2x untill the buffer gets a little slow
7 shots in raw
but for some reason never did
if i shoot RAW and jpeg fine on a d2x does it slow down the capacity to write images to the buffer then on the card
if so by how much, does it slow down the wite speed significantly?
in jpeg mode fine i can get at least 10 shots in burst mode on the d2x untill the buffer gets a little slow
7 shots in raw