You're doing better than me, then. i7-2600K @ 3.4GHz, 16GB DDR3. Windows 10, latest NVidia drivers. DoF and Motion Blur off, everything else maxxed out (with "Auto-Detect Settings" turned OFF, I recommend this), I'm sitting in the 50s most of the time at 1080p. Bear in mind I'm still at the beginning, this is all around the High Wall area. I'll be in the Undead Settlement tomorrow. Given your setup is a little better than mine, I'd expect similar performance.
Given that this is pretty much the same performance that everyone is experiencing, I'd say this is not really a GPU-limit and that something else in the code is causing it.
I did notice another odd thing tonight. Along the top of the screen, there's a band about ten pixels wide that appears to be tearing, like a V-sync issue. Those few pixels are slightly behind the rest of the screen when I turn the camera. But it never moves from that exact spot. I first noticed it a few days ago during a low-fps binge right after warping, but I thought it had gone away (I just don't really notice it when the framerate's high). The odd part is that it's purely an on-screen issue, the game is NOT actually rendering it that way. The Shadowplay videos don't have it, even in spots where I noticed it happening while I was playing (I can see myself whip-pan the camera in the video, but there's no artifacting whatsoever). Not sure if it's some kind of rendering or G-sync glitch, or a side effect of Shadowplay or something? Thankfully it's at the uppermost limit of the screen, and I honestly don't notice it at all unless I happen to look at it.