yes it is very possible... I just set wow to min graphics so it has little impact on Rift. I also run multiple instances of WoW all the time(each instance of wow would be considered another game)
so short answer is yes you can. Have a good day.
Well... He did.
See, how do you think people run multiple bots on one machine?
I guess what jawn meant is that your question can be answered by common sense.