The fact that the R9 290X is being cleared out for $300 to $350 is another fly in the ointment. The older card isn't quite as potent as the 390X--obviously--but that's a lot less dough. And if you already have a 290X, there's no compelling reason to upgrade to the 390X.
The R9 390X is a solid GPU, and Asus' Strix version is a great implementation of it. In most games, it delivers 90 percent of the performance of the vaunted Radeon Fury, but for $130 less. Ideally, it'd be nice if a 4GB variant was introduced at a sub-$400 price point, because the 8GB of RAM is pointless if you're playing at 1080p or 2560x1440, just to create a more compelling price/performance difference with the GTX 980 given the 390X's weak points.
But as it stands you won't be disappointed if you pick one up. Just be aware of its drawbacks versus the GTX 980, and aware of what you personally plan to use the card for. With that knowledge in hand, you'll be able to decide whether it's worthwhile for you to spend $40 to $100 more (depending on the model) for a GTX 980's vastly better power efficiency and overclocking chops.
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