Changing playback audio buffer size?

Hi,

https://preview.redd.it/f46w0lnt5qee1.png?width=743&format=png&auto=webp&s=18060d5b6295f2e169e94436f4aa208e23205973

I've got issues with audio lagging significantly (if I have an audio clip with the waveform visible, I can hit play, watch as it silently passes over the peak in the waveform, hit pause, and then hear the sound a second later), and troubleshooting advice recommends, after confirming that I'm using the right sample rates and audio device, to try lowering the playback audio buffer size.
The website says that this should be visible in the Preferences>Preview tab, but the websites own screenshot does not include that setting (my own view of the tab looks almost identical to the screenshot, except with a 'search profiles' button to the right of the Default Profile dropdown).

Is there something obvious that I'm missing, or is the guide out of date and this setting is no longer something that can be changed?