I noticed my 4G downloading some things even while I'm on wifi. and I in my battery stats, after a couple hours of use, I noticed it said it received about 6 MB of data. I'm attaching a screen shot. Does anyone know what it's downloading and if I can stop it? I don't recall this happening on gingerbread.
Are you sure that's 4G data? Data to the phone is data, whether it's delivered by mobile network, WiFi or Bluetooth.
(Your phone does use mobile data for sending and receiving MMS messages, though that data does not count against your data plan.)
If it is mobile data, it could be data delivered when the WiFi network was unavailable for some reason - disconnected, or perhaps a momentary DNS error with your broadband carrier.
As for the Android OS process and the data it receives, I believe it's anything that is received by an OS process in the background - account sync data with Google, Facebook, Twitter, or Backup Assistant, if you set any of those up; and I believe sync data for and home screen widgets that receive data (though those may be counted by the apps themselves.) I have a Droid 3 still on Gingerbread and "Android OS" remains the largest battery user on my phone by a long shot (currently Android OS 35%, Display 19%, WiFi 18%, Plume 9%, Phone Idle 7%, Cell Standby 6% - these are typical for my phone daily.) Gingerbread does not give discrete data counts for apps, though. The D3 and the Bionic on Gingerbread are essentially the same OS build; I'll bet that it was happening on GB for you.
