both are GREAT card for the $$
im running a 1600 and love it BUT
if you want raw frames i'd get the X850
if you want more detail (AA/AF/hi res)
i'd get the X1600
although the core and ram are slower it's a much better GPU
infact i don't think the 1600 core has pixlel pipes i think it's on the 100% new core....


look at this too:
http://www.tomshardware.com/2006/12/...for_the_money/