With music they will be in perfect sync. If paired as surrounds it will with TV.
If grouped with Beam as a different zone the Sonos Amp will be about 70ms behind the beam when watching TV as the Beam will be playing the direct digital connection and the Amp will be delayed as speakers are with wireless buffer. When listening to music on Beam it will have the same 70ms buffer and they will be in sync.
Respect the Queue (2)Move (3)Beam (1) Era100 (2)ARC (1)SonosOne (1)Playbar (4)Play5 (4)Play1 (3)Play3 (1)Port (2)Connect (1) Roam (2) Ace (1)Connect:Amp (4)Sonos Amp (1)Sub + (9) Echo + Smartthings; (2)Play)