Returning player, very low frame-rate.
Sounds like a pcie problem, get gpuz http://www.techpowerup.com/gpuz/ to check your bus speeds and make sure they are at x16 when you are running the game.
[ICoa] Blackgate
yea it really does sound like a PCI-E Link issue.
But also, I would recommend running the Beta 14.1 Drivers.
Across the board I am seeing a 8-12% performance increase for GW2, graphically speaking, but also better support for the older 5000 and 6000 based GPUs.
Desktop: 4790k@4.6ghz-1.25v, AMD 295×2, 32GB 1866CL10 RAM, 850Evo 500GB SSD
Laptop: M6600 – 2720QM, AMD HD6970M, 32GB 1600CL9 RAM, Arc100 480GB SSD
Laptop: M6600 – 2720QM, AMD HD6970M, 32GB 1600CL9 RAM, Arc100 480GB SSD