well im running swtor on a single core processor with 1.75 gb of ram. The lag is okay tbh. Its not enough to piss you off. If you have windows 7 here is my advice.
1. Right click swtor on desktop
2. properties
3.compatibility
4.check of run as administrator
5. run as windows xp
6.disable visual themes and desktop composition
7. end all programs/processes that you dont need
8. if u have norton uninstall it and get microsoft security essentials
9. update ur computer if needed
10. defrag if needed
11. end programs in the background(like volume control, i forgot how to do this)
12. restart ur computer
13. start swtor
14. go to preference, turn everything down to low and SHUT OFF shader
15. run in windowed mode and possibly turn down the resolution
16. go to controlls, and i forget what its called ontop of my head but turn it down to 0.00 (drop down menu on bottom of the tab)
send me a message if this worked.
my bet is u wont experience problems anywhere else but pvp warzones.Hope it helps