The effect is sharpest on mobile and on slower connections, where a heavy site can take many seconds to become usable. Every extra second increases the share of people who give up, and those are often high-intent visitors you paid to attract.
Speed also compounds with everything else. It improves SEO, ad performance (better landing-page experience), and user trust. Because it touches so many outcomes at once, performance is one of the highest-return technical investments a site can make.
Updated July 2026
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