i have two mbps pldt dsl connection and im using it alone sometimes 2 pc onky sometimes
i use dual core, 2gb memory and videocard
I see, No wonder you have lag issues, you definitely have a slow connection
PLUS, I could assume that you also suffer low FPS, even if thats dual core it cant do the job very well..
try to look on its clock rate instead, below 3 ghz doesnt do that much...
What OS are you running? 2gb is only good up to windows vista... If you install windows 7 your loading time would be very slow..
and the memory size of videocard does not affect how the graphics is process.. tantra graphics only occupy a small space in that memory.. The most important to look for its benchmark on how well it can process 3D graphics.
look for your video card is this website:
http://www.videocardbenchmark.net/anything below a score of 1000 will definitely experience low FPS