updated my Lumia 1020 yesterday evening. immediately after the update it was the same. I let it drain to shut down and charged it all the way. I then turned on background on all my apps, switched to LTE from edge and set my email to push from every 30 mins to get an accurate idea of any changes (the previous settings were in place to make sure I could get a full day on GDR2).after 5 hours and 6 minutes which included 1hour off Wi-Fi, 1 hour of calls, about 10-12 pictures, some texting tweeting and about 3 pictures to Facebook and 3 to 6Tag, I'm now at 82% which is much better than it's been before considering how much I had it limited previously. I'll report back once I've drained it down to 0 to let you know what my final results were.