680 is still really good. What is your cpu? It might just be worth upgrading that instead. It will be best though to wait until AMDs new cards are released for prices to drop, or you can alternatively buy a used 680 for SLI.
The only real reason to get this would be for the looks, because air coolers like the nh d14 are comparable for less money.
http://www.tomshardware.com/reviews/h100i-elc240-seidon-240m-lq320,3380-14.html
Nice step into the future tbh, I'm partially glad that it is coming from AMD as they need an edge after being outclassed in nearly every market they're in
I would wait for hawaii to land so prices drop and then try picking up a reduced price 770 or 7950, depending on your budget. Your cpu is still pretty good, but if you want to upgrade to haswell it wouldn't hurt.
A 940 will probably bottleneck a 7950, but if the lag described isn't fps related then try lowering the resolution as there might be some driver conflicts.
I'm lucking for 3 new monitors for an eyefinity set up. I'm planning on spending around 350$ on monitors. I currently have an HP w2338h, but it is bad for eyefinity (1inch thick bezel. Advertised 23", only 20" screen. 1920x1080).
I'm looking for something cheap, but good. lol
My local comp...