I guess I shouldn't have said "constantly" I know the GS3 searched in 30 min intervals, but to that point I noticed a difference in my GS3 battery life with LTE enabled but only getting 3g service.
I noticed my Exchange account for e-mail was draining my battery, probably because its not working properly. Removed the account, haven't had issues since. I'm going on 5 1/2 hours unplugged as of this post, and I still have 90%.