Originally Posted by
patrickwee Recently has lot of user compliant that after updated their Windows phone into gdr 1 has facing lagging when tap the home button , now I have found some tricks from other websites whereas you just unpin your Cortana tile it MAY solve the lagging problem . Hope this help .
I too, was suffering the same problem. I am running 8.1/Cyan update 1. I decided to try removing the Cortana live tile from my start screen. This solution did work for me. My L520 runs as smooth as butter now, whaddaya know, go figure.