Snapcast client playback stalls buffers

I have a raspberry pi 4 running as the snapcast server, which plays songs from my network drive, both connected by cat5.

Couple of other raspberry pi’s (3 probably) on wifi running as clients, even when just one is running I often get stalls, gaps of silence in tracks. I’ve tried moving an access point to meters away to check it isn’t a wifi issue and I’m not sure what to do to remedy the issue. Are they not powerful enough? Could they need a better SD read rate (I doubt it writes to this but uses RAM) I’ve just been trying to correct the problem for some time but networking isn’t really by area and I have no idea of the kind of resource level that the devices need to playback or encode.

Thanks in advance for any feedback.