Which Browser is the Fastest?

One of the common questions asked in the web performance space is; which browser is the fastest?

The answer I am afraid is It depends.

What we find is that different websites work better from a performance perspective on some browsers than others and there is not necessarily any commonality in the findings.

Website Performance By Browser – Some Examples

Website Number 1 - Performance

Lets have a look at the median page performance for a section.io customer over the last few days as measured by browser;

browserspeed median P

(note y axis scale is in milliseconds)

This graph would indicate that IE and Chrome are the faster of the browsers while Safari (Mobile) has some serious performance issues. Is this a problem with the browser or the web pages? (or both!) and what should be done to improve the performance? Prima Facie, we would look at this intelligence and start work straight away on improving the website performance for Safari (Mobile) users. We will have a look at whether this is the right answer later in this post.

Website Number 2 Performance

Having a look at another section.io customers median page performance by browser:

Browser performance M

We can see here that generally, IE is one of the better performing browsers while Chrome, Firefox and Safari dont seem to score as well.

Website Number 3 Performance

Finally, a third section.io Customer shows somewhat differing attributes for their browser performance;

Browser performance LJ

In this case it is Firefox and IE which dont score as well while Safari, Chrome and IE are the winners.

Each of the above websites are very different. They have different content, page weight, page construction and integration of third party content. In addition there are major differences for each site in terms of user bases and how or when the users user the sites.

However, each of the these sites have benefited from improving website performance through greater customer engagement, reduced bounce rates, improved SEO and / or improved conversion rates.

Improving Website Performance by Browser

As part of section.ios performance management solution, our task is to review these metrics and pull the right levers to continue to improve performance for the users overall. In the case of websites 1 and 2, performance is pretty good in the 2 - 3 seconds per page. However, there is still room for (and reasons to pursue) improvements in page performance. To get the best bang for buck, it is important to focus on the right areas when undertaking a performance management solution.

Website Number 1 – Area of Focus

Taking the first of the websites above where Safari (Mobile) was the worst performer, you would be inclined to focus on that browser. However, for this particular website, that browser is not commonly used. We calculate the overall page performance cost of each browser by multiplying the page loads for each browser by the pages loaded. See following;

Browser Impact P

By viewing the data in this fashion we can quickly discover that the best way to improve performance for the most users, is to improve performance of the website for IE even though it is already the fastest of the browsers.

That is not to say these numbers should be considered in isolation of the business digital strategy. It could of course be argued that no one is using Safari Mobile because the performance is so poor. Therefore, some understanding of the business digital direction is also important.

Website Number 2 – Area of Focus

Website number 2 displays a different browser performance cost;

browserimpact M

For website number 2, Chrome and IE would be the targets for website performance improvement. In this instance, Chrome is both a poorer performer than other browsers and a very commonly used browser.

Website Number 3 – Area of Focus

Finally, website number 3 displays completely different browser performance cost attributes. Safari Mobile and IE would be the ideal areas of focus. While Safari (Mobile) was a stronger performer, it is obviously a popular browser for Website Number 3 while IEs performance attributes and medium utilisation make it a target for focus.

Browser Impact LJ


While there have many studies to understand the performance of browsers in terms of boot time, navigation and rendering, there are very few which look into the performance of browsers on a site specific basis.

As a user, I will choose the browser which has the features and usability I desire. Website owners should seek to make sure websites are delivered in the best possible way to allow the large variety of browsers to receive and render the site as efficiently as possible. In particular, website owners should understand the mix of browsers their users work with and what the performance characteristics of their website is in each of the browsers. Then, to get the best improvement for the most users, focus on those browsers where the performance cost is highest.

This performance cost by browser focus can also then be extended to performance cost by specific area of a website; e.g. Home Page, Category Page, Product Page etc. However, thats topic for another day.

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