<b>Delay the ad script ~1 second, watch RPM climb</b>

<b>Delay the ad script ~1 second, watch RPM climb</b>
Counterintuitive one. Loading the AdSense script dead-first slows your page, hurts the user, and you bid into a slow page.
Deferred the ad loader by about 800ms after first content paint on one site.
— LCP improved noticeably
— viewability up because content was visible first
— RPM +9%, fill rate unchanged
The ad doesn't need to be the very first thing. Let content paint, then load. Test it on one page first.