Is a 200ms decrease in page load time significant?

问题:

I made a few tests with lab js in one of the sites I've developed and got a reduction of 200ms in the page load time. The total time spent now after backend processing is around 1.5 seconds.

I was wandering if its worth the trouble. Is 200ms a huge gain? A ridiculous one? I know that page load times affect page ranking, but 200ms will make such a big difference?

回答1:

Quoting Milliseconds are Money: How Much Performance Matters in the Cloud:

5) The Proof That Milliseconds Matter …

The big guys in the cloud industry have really dug deep and proved that those milliseconds matter:

• For every 100ms increase in load time of Amazon.com decreased sales by 1% (Kohavi and Longbotham 2007).

• Google discovered that a change from loading a 10-result page in 0.4 seconds to a 30-result page loading in 0.9 seconds decreased traffic and ad revenues by 20% (Linden 2006).

• Google Search found that a 400 millisecond delay resulted in a -0.59% change in searches/user. What’s more, even after the delay was removed, these users still had -0.21% fewer searches, indicating that a slower user experience affects long term behavior.

• Another study by Google found that an extra 500ms in loading time resulted in 20% drop in traffic.

• Yahoo also found that a 400ms slower page would see 5-9% more people leave before the page finished loading.

I think this answers your question.

回答2:

An absolute 200ms gain is not a huge gain IMHO.

But... If you spend several days optimizing and each day you manage to gain 200ms, it will become significant.

What you should ask yourself is: when I open my page, do I feel like clicking away or not? As if you were a clicking-away caffeinated monkey I mean.

If you feel like staying, then don't optimize. If you feel you saw too many microseconds of empty-white-page before the page loaded, then continue optimizing.