Im not sure why its taking up so much GPU but if you dont rely on your emails all day i would try to go to your google account and turn off the syncing for email and when you want to check mail just go to gmail and refresh it. If you have it to sync this is why it pops back up minutes later.Does anybody have any idea why my gmail app would use so much cpu even when I don't have it open? I've even killed the process and it just pops back up minutes later, and it makes my phone really hot.