Case: fixed multi-size slots beat one responsive slot

Case: fixed multi-size slots beat one responsive slot

What it did: replaced a single fluid responsive in-content unit with a fixed slot offering 300x250, 336x280, and 728x90, letting the auction pick.

— Setup effort: 2/5 (size mapping in GAM)
— RPM lift seen: that slot $4.10 → $5.05 RPM (+23%), page RPM +6%
— Why: 336x280 and 300x250 pull far higher CPMs than the small responsive sizes the fluid unit kept serving

Pros: you stop letting Google downsize you into cheap formats.
Cons: must reserve height for the tallest size or you reintroduce CLS; set min-height to 280px.

Lift: ★★★★☆ — Risk: ★★☆☆☆
Verdict: explicit size lists beat lazy responsive on in-content slots. Best for: anyone using fluid auto-ads. Skip in tight columns under 300px wide.