Pi Zero Stutter/Glitching

[BuToNz]

Hey guys,

Using a Pi Zero in a project and have found that when in game the audio/video will glitch every 6-7 seconds. Is there a process which is running in the background which could be causing this? I've tried disabling rewind, smoothing, WiFi, Bluetooth, using different cores, a 'lighter' skin (Pixel TFT) and doing a fresh install with only a single rom loaded. All have this slight glitch/lag.

Doesn't seem to be an issue on the Pi3 so I'm thinking something is taking CPU time up every 6-7 seconds?

Monitoring via the web interface shows CPU barely ever hitting 100% but refreshing the page causes lag anyway.

Any ideas and/or suggestions?

:EDIT: It's very subtle and only really noticeable when playing something like Mario where timing is crucial. It can be seen in this video: https://www.youtube.com/watch?v=1kXB_9y9-ZE @ 4:15-ish

[RustyMG]

You HAVE tried switching "rewind" off?

[BuToNz]

@RustyMG it's off by default on the Pi1/zero build but have tried toggling on and off.