Hey I just tested starcraft 2 right now on low setting. I still don't know if you can play it, but it only used my GTX about 26% on all low setting 1920x1080. It looks bad though. I guess the only way is to try the demo when it comes out.
Demos have already been out for a while and SC2 is coming out very soon, so if you mean wait for SC3, wait another 10-15 years,