UT3 has no chance of running on 2GB of RAM.
I would get some more, and buy a good Video Card, even though the one you have looks halfway decent...
Set the process on high priority.
Also, take a look at this, though I don't think it will help since you have half the RAM I do.
But setting your virtual memory on the recommended amount will only work in your favor.
https://www.mpgh.net/forum/197-combat...s-gfx-lag.html