GTX 1080 vs R9 390 benchmarks. Should I return the 1080?

Sounds like you've already hit a bottleneck with the rest of the system. A GTX1070 might be a better option for you. Then you can save some money will you wait for Vega or Volta (or whatever Nvidia's next one is, they keep changing it)

Nothing wrong with the 1080's performance today. Which is kind of how I view it. Power today with Nvidia, AMD slow driver improvement. You can argue the other way as well, why doesn't Nvidia do this as well (or have they already done it). Or why doesn't AMD do this kind of thing up front to get the most performance possible on release day.

Nvidia does drop cards, but they are usually pretty old by the time they do. And someone willing to buy flagship cards shouldn't concern themselves too much about it. It also seems AMD is more willing to try new technologies, which is why some of their older designs stick around for longer. They were built with the future in mind.

I would say it depends on some things:
1) Micro Center's open-box return policy. I personally love shopping for parts there, but if they won't take a return on the open-box then you might as well keep the GTX 1080 (or try selling it).

2) I'm assuming your monitor is capable of 1440p resolutions. If so, do you like the picture quality with the GTX 1080 @ 1440p better than the quality with the R9 390 @ 1080p? If you prefer the higher resolution, then keep the 1080; aside from the new Pascal Titans, it's the king of GPUs, so even with "planned obsolescence" it should still be at or near the top for another year. If you don't like the quality as much, then take back the GTX 1080 & save your money (assuming #1 allows you to).



3) There's always another "brand new, now it cleans your monitor screen for you!!!" GPU coming down the pike; that much hasn't changed. What's changed, however, is the approach in the GPUs -- both in the marketing & in the capabilities. Time was, each new GPU that came out (nVidia, ATI/AMD, Voodoo, S3, etc.) was all about improving on both the prior GPU they built as well as one-upping the competition. Nowadays, however, it's not enough to just have a "super-turbo-screaming-fast Death Machine" of a GPU that will partially handle Crysis 3 & Ashes of the Singularity, you have to have GPUs that appeal to all of the markets. Some of us, for example, just added a 2nd monitor to their PC setup (desktop use only, not for gaming, since its resolution is lower than my primary monitor), & are still primarily gaming at the sub-1080p resolution (primary monitor hits 1600x900 tops). For us, a top-line GPU like the GTX 1080 is not only super-overkill for our gaming needs, but by itself almost doubles the cost of the gaming PC we would build...& is therefore nowhere near worth the money for us. When I buy my next monitor, though, it'll be because the current one went bad, & unless they simply don't make them anymore -- which I'll know is on the horizon when Tom's Hardware lumps the "Recommended for eSports" and "Recommended for Full HD" categories into a single one -- it'll most likely be a 1080p monitor (most likely with a 60Hz refresh rate). Right now, if you're happy at 1440p resolutions, that GTX 1080 looks like a solid GPU to have (aside from apparently some overheating issues a few models are having), so I wouldn't worry too much about what nVidia or AMD plan on bringing out next year. If you're that worried, though, about its future capabilities but don't want to just rely on your R9 390, then like @Eximo said I would consider returning the 1080 & just getting a GTX 1070 (assuming #1 isn't a problem, & assuming the open-box cost on the 1080 was so low that it brought it down to a 1070's price).

Hmm, then you must have V-sync on or something on to hold back the GPU from reaching 100% utilization.

It would have been nice if they kept their promise to add DX12 support via drivers to the Fermi line, but Kepler did get it, which is still going back a ways in terms of GPU.

AMD hasn't made too many drastic leaps with GCN, but they do tend to be on the cutting edge. It is bad in a way, it means that almost nothing supports what the card can do when it comes out. And that when it does, your high end card is the equivalent of a new mid-range card.