Can't Achieve Realtime Playback When Introducing Audio

[AXXXXXXXXX]

My dilemma:

I ram-preview my work at full resolution and I can get real-time playback – all is good.

As soon as I introduce audio — all is bad.

What I've tried:

I drop the resolution to 1/4 – nope.

Then I set skip frames to 5 — ok I'm getting some realtime, but I simply cannot work with 5 skipped frames.

Yes, I'm caching the frames — still nothing.

What gives? Why is audio giving me such a hard time here?

I'm running a Macbook Pro M1 MAX w/ 32gb RAM

Ae 2023 

[Rick Gerard]

If you use an MP3, try converting that to a 48 kHz 16-bit PCM WAV file. Audition is up to the task. 

[AXXXXXXXXX]

Thanks, but I'm already using WAV files 0.0