Google Voice SMS - phone sleeping?

[bweave]

I moved to using my Google Voice number (through Hangouts app) for SMS almost exclusively recently. What I find though is my M8 does not 'receive' the message nearly as fast as my tablet or pc (sometimes a gap of 5 minutes). There are times that, the only way to get the SMS is to unlock the phone and open Hangouts.

During this time my Gmail and Emails that are pushed all come through.

Anyone have any thoughts?

This is a stock device on the Verizon Network.

Thanks!