A current i5 CPU may be vacated in favor of a newer-generation i5 or even an i7. It just depends on the MOBO. Try this site: Pick Parts. Build Your PC. Compare and Share. It lets you assemble details on hardware builds and checks for compatibility. You can specify your MOBO and a processor then see if it yells at you. This site even sports videos on building a computer with recommendations, practices, etc.
—thanks to Jacob Collings.