Site speed affects SEO through two channels: as a confirmed ranking signal and through its impact on user behavior metrics that Google tracks. Since 2010 for desktop and 2018 for mobile (the Page Speed Update), Google explicitly uses load time as a ranking factor. A site that takes 5+ seconds to load will struggle to outrank a comparable site that loads in under 2 seconds, all else being equal. The bigger impact comes from user behavior. Internal Google data shows that as page load time goes from 1 second to 3 seconds, bounce probability increases by 32%. From 1 to 5 seconds, it jumps 90%. From 1 to 10 seconds, 123%. When users bounce quickly or don't engage, Google interprets that as a quality signal. You might have great content, but if half your visitors leave before it renders, your rankings suffer. Core Web Vitals formalized this in 2021. Google now measures Largest Contentful Paint (how fast main content loads), First Input Delay (how quickly the page responds), and Cumulative Layout Shift (visual stability). Sites that fail these thresholds get labeled as providing poor page experience. We've seen competitive niches where fixing CWV issues moved pages from position 6 to position 2 within weeks. For Canadian e-commerce clients, we typically see conversion rate increases of 15-25% when LCP drops from 4 seconds to under 2 seconds. That's not just SEO value, that's revenue. The ROI on speed optimization is often better than link building for established sites. Practical impact varies by niche. If you're in local services competing in Ottawa or Toronto, where most competitors have slow WordPress sites with bloated themes, even moderate speed improvements (getting to a B grade on GTmetrix) can create ranking separation. In technical SaaS or finance verticals where competitors are already optimized, you need sub-1-second LCP to stay competitive. Speed optimization is also cheaper than most SEO tactics. Upgrading hosting, implementing proper caching, compressing images, and deferring non-critical JavaScript costs less than one month of content production but delivers compounding returns across your entire domain.