I fancied a switch over to ART runtime with Nova launcher to see how the performance weighs up. It took a while for it to optimize and change over but everything seem fine in the end except for one problem, I can't use mobile data. I've tried wiping the cache partition and resetting the APN to default with no avail. I'm recently switched to Three network while I was EE it was working perfectly fine. Could it be a problem with the network not working with ART runtime?