This app was mentioned in 4 comments, with an average of 1.00 upvote
Out of curiosity, run this program when you can: https://play.google.com/store/apps/details?id=com.passmark.pt_mobile&hl=en
I usually get a overall score of around 2500. Run it a few times with no other apps open and see what you get.
Maybe you and others that have problematic Moto G's got some bait and switched version. I have one only and it is simply smooth all day for me.
The one i ran was PassMark: https://play.google.com/store/apps/details?id=com.passmark.pt_mobile
App used for benchmark: PassMark PerformanceTest
https://play.google.com/store/apps/details?id=com.passmark.pt_mobile