Your processor is pretty sub par at 2.8ghz.
The 780 is a hungry card, it needs to be fed with an army of dump trucks and you have a pickup truck.
In other words, it sounds like your processor is bottlenecking and unable to load your GPU fast enough so your GPU is not running at full load. This would explain why you lag in toll by the crystal, there are a lot of people there and a lot of processing for your CPU to do, it's just not fast enough.
Get an I5-2500k and overclock it to 4.7 ghz and you should see a HUGGGGEEE boost.
Buying a great graphics card isn't always going to net you an increase in performance. Your computer is only as strong as it's weekest link. Your CPU needs to be capable of loading the 780 to max, and it's not. Also your hard drive needs to be fast enough to load textures and stuff into ram for your CPU to load them into the GPU and it might not be either.
An I5-2500k, a 760, and an SSD would have been a better upgrade. The 780 is a better card, but you need the CPU to go with it.
Unfortunately if you want to go i5-2500k your going to need a new MOBO because your CPU is 1st gen.
