Is the game's performance or SLI scaling glitched or something, or is it just that ridiculously difficult to run?

I'm running a GTX 590 at 1680x1050 with 1xSMAA, all settings and textures at very high EXCEPT for particles (medium), shaders (high), and shadows (high), and my FPS drops to 25-27 on the first level of the game (when you get the bow for the first time, looking out onto that stormy deck). I was expecting my FPS to stay around 45 fps, but dropping down that low seems absolutely ludicrous.

I realize that my card isn't exactly the Geforce Titan but nevertheless it's a really high end card (performance just above that of a 680) So I'm not really sure what to think right now - Is the game running normally or is it a performance issue, SLI scaling issue, etc?

EDIT: CPU: i7 2600k, hyperthreading off, overclocked to 4.4
RAM: 8Gb Ripjaws

I run a gtx 560 ti o/c 999mhz core and I get 25 fps at 1680x1050 on vh but no aa. Sounds like a driver issue. You should be getting way more frames than that.

Agent 009, I run it at 45+fps most of the time on the first level... The drops to 25-27 fps are very infrequent. In fact there's only actually been one point, which was the point where you get the predator bow at the beginning of the game.

I'm running drivers version 314.07.

The only dip I really got was when you first enter the fields. It acts like it's lagging from loading textures. Does it no matter what res I have the textures at. Other than that smooth. I'm usually at 30+ but it always goes to 20-25 at the fields map.

I'm sure I read a thread elsewhere on the forum from a 580 owner stating his card was only utilizing 1 core, you might have the same problem. I don't remember reading a solution.