Apple tv airplay stutter/lag after updating to Mac OS Sierra

You aren't understanding what I'm saying. Everything was fine, never any stuttering or problems with my old macbook which was a 2008. Then I get a new one, update to most current Sierra, and it stutters. Not randomly or haphazardly, but every second like clockwork. If mirroring is so intensive, why did my old crappy slow macbook have no problems on the same network, same apply tv, same everything? Also, the Apple TV is connected to ethernet and there is no other activity on the network. If that's considered troubleshooting, I did that already.

I understand perfectly well what you are saying.

Mirroring requires a Mac from 2011 or later, so it wouldn't have been possible on that computer.

What were the results from the network report? How old is the router? Is it up to date? Did you test on another network?

Oh, you're right. I didn't airplay from my old macbook. I did from my Imac and from my iphone, no problems. The router is a few months old. Brand new router/modem with fiber optic internet 200 Mbps. I don't have another network to test.

istumbler says:

level: max

signal: -40dbm

noise: -96dbm

nearby networks: there are 2 but they are low signal

That will be due to your network. Other devices working doesn't rule that out and there is a big difference between using AirPlay on those devices and mirroring your Mac's display in realtime.

If on wifi try connecting Apple TV via ethernet

Make sure no other activity is taking place (other streaming or web use, network backups etc)

To see a current status of the network get a report from istumbler or similar. Look for signal strength, noise, nearby networks

Test on another network

I have this issue too, and it was only after an update. My network is super fast and so is my router. I get 100Mbps wifi. It's NOT the network. Please help.

Network issues can come at any time, and this is over the local network so Internet speed is irrelevant. Proper troubleshooting needs to occur

But this does it every time I try to Airplay. Morning, afternoon, night. No other problems with any other devices and the network. What troubleshooting needs to occur?

Mirroring is very intensive as it is sending out your full display in real time. Other devices working doesn't rule out a network issue, the suggestions were already outlined above

Try changing channels on the router

You would be going to another location to test on a different network

I've tried 5 different channels, same issue, no change. How would I go to a different location? You mean take my 45 inch TV, my Apple TV, and my computer somewhere?? haha.

I've figured out the solution: bluetooth! I turned off bluetooth on my macbook and it ran like a charm! Apparently the bluetooth signal was interfering with the airplay. Such an easy fix!