Since it is about 7870, may I ask some question here.

I also using 7870, I can set graphic to maximum and run 60 fps just fine in dungoen.
But when in crowd or in open map, fps drop to 20-40 fps.

Just change to SSD recently, it helps to load map in open map smoothly but still not improve fps.

My spec is

CPU : FX4100
VGA : HD7870
Ram : 4GB DDR
SSD : Samsung 840 Pro 128 GB
PS, I am using 40" LED TV as a monitor, not sure if it is effect on performance of VGA.

I am guessing I should upgrade CPU, will it help ?