I thought it is just me. My Lumia 820's start screen was smooth and lag free before updating to update 1. now it's lagging and indeed even after reset and yes i am using a background not accent color. what's also weird is it's as if the live tiles became placeholders for the apps instead of the app shortcuts themselves. you see, when i scroll very fast in the start screen, im only seeing my background and the squares but i don't see the apps. only after the scrolling does the app icons/colors/live reappear with noticeable lag too. it's as if a webpage is loading with photos. I am beginning to think WindowsPhone's reputation of blazingly-fast-lag-free experience is on the rocks-about to keel over and fall.