What it means is that the tasks your using don't require more RAM then one gig. If it helps, think of it like this. You don't get more FPS by having a 500GB harddrive instead of a 250GB. More doesn't equal better. As others have pointed out, by losing dual channel your losing speed you might have got by adding the extra gig.
I say, keep it in. You now have two gigs of ram, and your computer isn't any slower then what it was. If/when you start to need more then a gig, you'll have it.