which is the best graphic card that is compatible with asus m3n78-em
More aboutgraphic cards compatible asus m3n78
Your motherboard has a PCI-E 2.0 x16 slot. That means it can use any PCI-E card, which means almost all current cards. What is more likely to limit your card selection is your power supply and possibly your processor.
Agree with jyjjy... Tell us your full specs and how much do you want to spend on this new card?