Instant.Page does one special thing to make sites faster: it preloads the next page when it’s pretty sure you’re going to click a link (either by hovering over 65ms or mousedown on desktop, or touchstart on mobile), so when you do complete the click (probably a few hundred milliseconds later), it loads that much faster.
It’s one thing to understand that approach, buy into it, integrate it, and consider it a perf win. I have it installed here!
It’s another thing to actually get the data on your own site. Leave it to Tim Kadlec to get clever and A/B test it. Tim was able to do a 50/50 A/B split with performance-neutral Netlify split testing. Half loaded Instant.Page, the other half didn’t. And the same halves told SpeedCurve which half they were in, so performance charts could be built to compare.
Tim says it mostly looks good, but his site probably isn’t the best test:
It’s also worth noting that even if the results do look good, just because it does or doesn’t make an impact on my site doesn’t mean it won’t have a different impact elsewhere. My site has a short session length, typically, and very lightweight pages: putting this on a larger commercial site would inevitably yield much different results.
I’d love to see someone do this on a beefier site. I’m in the how could it not be faster?! camp, but with zero data.