I was flying last night and averaged 15, 10 when I had the Shkval on. I have everything on low except vis range and terrain (both high). Cockpit shadows on, HDR normal, VSynv off, TSSA and AF throught NVidia control panel only, running at 1900x1200. Also had tree view distance at 10,000m, but after I quit I dropped that back to minumim as well. Jumped up to about 22 or so after that... Flyable, but not overly enjoyable..
GTX 260
E8400 Dual core
8 Gb RAM