Hey everyone first off thank you very much for reading this post and for any advice you have to bring to the table. I am currently thinking it is time to upgrade my GPU it has been almost 3 years since I built this system. If I am fine for my GPU feel free to tell me but upgrading GPU every three years is something I normally do. My budget is around the 350$ mark and I plan to have it power 3 displays a 27" Asus Display port monitor and 2x 24" Asus Monitors with HDMI and DVI on them. Preferably the card would be able to use Diplay-Port for the 27" and HDMI for all the 24" and since it is using a p7p55d-e using SLI or Crossfire isn't the best idea to my knowledge do the the limitations of turning the power down to 8x on each card.
Currently I am using a home built PC with specs:
Ram: 2x2 Corsair 1600
Motherboard: Asus P7P55D-E PRO
HDD1: Intel 80g SSD
HHD2: 500g Samsung
GPU: XFX Radeon HD 5870 2g
PS: 650W Corsair
If you want to get both side monitors the 24"ers running HDMI (im assuming for sound), then you would need one mini display port to HDMI adapter, im also not really a fan of visiontek, oddly enough its because of thier fans, lol. The 7970's will beast that setup on 1920x1080 and shouldnt have much trouble with 2560x1600. Your probably going to have to raise your budget $50 - $80 for a 7970, you could go with a 7950 to stay within your budget, but since your running 3 screens id recommend the 7970.
Well your best bet on your budget is Sapphire's HD 7950 Vapor-X comes with a large dual-fan cooler that uses the company's famous vapor-chamber technology. On the Vapor-X you will also find a "Lethal Boost" button which switches to a second BIOS with higher clock speeds. With this BIOS, clocks are increased to 950 MHz GPU and 1250 MHz memory. $319.99 $299.99 after $20.00 rebate(s) http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Ahhhh, im using a 7950 Gigabyte 3x Windforce OC'ed tp 1000Mhz it works amazingly for me, but i only have one monitor, a 39" LED TV also HDMI connected, I get around 90-70 fps in GW2 on max @ 1920x1080. So you shouldn't do too far off that with a base clock and 3 monitors, maybe 50-70 fps im guessing.
Honestly for the kind of set up you require $350 just won't cut it like i mentioned on your budget Sapphire's HD 7950 Vapor-X is your best bet and according to what MotherFerJones said doesn't seem like you'll do to bad anyway good luck!