While the performance increase on iOS 7.1 appears genuine - I'm experiencing serious battery drain on my iPhone 4S (64GB model). I have parallax disabled as well as background app refresh disabled. I updated from iOS 7.06 to 7.1 via USB cable attached to my Mac Pro and the latest version of iTunes running on Mavericks latest version as well. I had closed all apps and done a reset before connecting to iTunes where I did a backup and sync prior to updating. The drain I'm experiencing is during usage, not standby as much. When I use my standard apps (mail, safari, txt, etc.) I'm seeing the battery drain about 1% per minute. I'm not using GPS or bluetooth. I followed one suggested on Apple Forums to drain battery to about 40%, then do another hard reset. Doesn't seem to help. Anyone know of similar issues or what to try next?