Why apple uses ati cards?

recently apple started shipping their iMac,Mac Pro and macbook pro with ati radeon video cards!!!

whereas ati doesn't supplies any drivers for apple products,,whereas nvidia which supplies drivers for

all O.S's in the world??why apple doesn't uses nvidia???|||ATI doesn't exist anymore. They were bought out by AMD and renamed.



But to answer your question, probably because AMD offers Apple better prices. Pretty much the same reason any business bases it's purchasing decisions on.