prices are subjective and vary by region. but here is something that stays consistent, average power draw during gaming,
GTX 980: 156W
390X: 344W
that's pretty darn awful if you decide to go CF. during a long gaming session 400W of extra power is going to turn your room into a sauna on a summer day. i know this because i was once a not-so-proud owner of a pair of GTX 480. and never mind the few extra dollars a month on the energy bill. AMD can't possibly charge the same price for a 390X.
back on topic, this stuff is pretty much pointless. we need actual games to see which cards are better. no one buys these cards to run half ass demos on beta drivers