Don't know if its been discussed before but Google are testing a new system called ART which will eventually replace DALVIK, The aim is to increase efficiency, execution times and improve battery. I have had it enabled on my N5 for about 12 hours now, will know what impact it has on the battery by the end of the day. Here's a bit more detail:
http://www.androidpolice.com/2013/1...-in-secret-for-over-2-years-debuts-in-kitkat/
http://www.androidpolice.com/2013/1...-in-secret-for-over-2-years-debuts-in-kitkat/