Guild Wars 2

I recently get a new computer with spec:
I7 4770K
16GB DDR3 2133
120G SSD
ASUS Sabertooth Z87 Motherboard
MSI HD 7990 Graphic Card
Win 8.1 pro

I was expecting running full settings with wvw in this game, however, it only gives me around 15-25fps in it
25-45fps in LA. lower down the setting helps a little but not that much.
When I checked ccc, it shows that only 1 of my 2 cores of 7990 are running, at 70~100% activities and second setting at 0%
I tried to swap to my old graphic card gtx560ti, and the performance is not that much of a difference.
So is that my problem, or anet’s? if it’s my problem, how can I fix it?
Thanks for the help.

btw I have downloaded and installed the newest version of drives: 13.11
Checked all my settings and updates. used cc cleaners, problem still occurs….

There is no hardware capable of rendering this game at highest settings and decent fps.