The CPU count means nothing. The G3 will rarely run on all 4 cores or at max. If this is on wifi with slow speeds, this is a known issue to be fixed with 5.1 hopefully.
Had the same problem. Started happening right after the lollipop update. Here is how I fixed the problem...go to settings...mobile networks...system select and change from global to lte/cdma.
OP speaks of CPU usage. I was speaking to that. the network switch trick works at times, but the phone will eventually switch back to Global.
In that case i'm lucky. I set my g3 to lte/cdma and it hasn't budged from there. Except for when i first bought the phone and was fiddling around with it.
Have you considered a factory reset? That fixed all my problems with sluggishness, data usage, etc. My only mistake is that I didn't unmount my SD card, and it trashed everything on the card except my gallery items (photos and videos). I had used Titanium backup to back up all my apps, and I had to end up reinstalling everything manually because it deleted the backups.
My phone is 1000% better since the factory reset. I have also resisted the urge to update to lollipop. I'll wait for 5.1 or whatever update Verizon pushes and see if things get any better than what they are right now (judging by all the complaints here).
Depending on where I went, especially in fringe areas, the phone would revert to Global if it found no signal.
Oh. That's another story then.