Exhibit #1 to the Jury, ladies and gentlebeings. I've got a Intel Core 2 Quad, at 2.8Ghz OC'd, with 8GB RAM, and a Twin Frozr II 460Ti on Windows 10, and I get about the same frame rates. The issue here is not the framerates. The issue is that the gameplay didn't seem to stutter, or freeze. The OP is going based on a number, not an actual quantifiable experience. He seems to think that unless He is getting 60-80+ FPS, the game must be unplayable. I have played since launch with an average FPS of about 40, even when Open World PvP was actually a thing and you had an unscripted battle of 20-30 on either side. Occasional lag with lightning storm going off every three seconds, but on the whole, totally playable. I have never lagged out of a WZ, and I DID play as a competitive PvP Sage Healer (pre-nerf). NO issues at all.
So I guess what I am saying is appreciate what you have, and stop being a perfectionist? The game runs fine on your PC.