Why am I lagging so much on GW2??

[Ty2012]

Hey there people, I was wondering if anyone could tell me why my pc lagg so much playing guild war 2, I just recently brought a new graphic card and update my rams. I get only 5-8 frame rate in city and 8-15 frame rate in world map. I'm running everything low and none on graphic setting. Any advices is helpful for me thx.
AMD Athlon 64 X2 3500
2.1 gz
ATI Radeon HD5450 DDR3 2GB 64bit PCI-E
4 gig rams
Window 7 pro 32 bit

[Deleted]

Don't know what it could be, but what does it say here
http://www.systemrequirementslab.com/cyri/intro.aspx ?
Just type in guild wars 2 or chose it from the dropdown menu.