Speed

What is it?

Measures the speed of the website on a specific device (desktop or mobile).

This test measures:

• Load time – how long pages take to fully load, i.e. all of the parts of the page have loaded, except for resources which never finish (e.g. some video, web sockets, or polling resources).
• Interactive time – how long users must wait for a page to become usable, i.e. enough of the page has loaded that text can be read and links could be clicked on.

This test also makes technical recommendations on how the speed of individual pages could be improved.

What checks it covers

The speed test checks for the following for each webpage:

• Is browser caching enabled?
• Is HTTP/2 used?
• Are CSS files minified?
• Are JavaScript files minified?
• Are appropriate files compressed via GZIP or equivalent?
• Are any files missing?
• Are any elements blocking the render?
• Are any pages slow to load overall?
• Are any pages slow to respond (TTFB) overall?
• Are images optimized for speed/size?
• Are there excessive font files on a page?
• Are there excessive JavaScript files on a page?
• Are there excessive CSS files on a page?
• Is the HTML for the page too large?
• Is the CSS for the page too large?
• Is the JavaScript for the page too large?
• Are the fonts for the page too large?

Speed recommendations are often technical in nature and may require a qualified developer to implement.

Targets

By default this test checks for these targets:

• Good 3G connectivity, using an equivalent to an iPhone 5
• Desktop using broadband over wi-fi
• Measured from North Virginia in the United States

Why it matters

Speed is one of the most significant aspects of website user experience. Users are more likely to abandon websites the slower that they are, and the sensitivity to speed is extremely high; an Amazon study discovered that every 0.1s they added to their load time resulted in a 1% reduction in sales for that user.

Speed is now considered a ranking factor by Google, meaning that slower websites will, on average, rank lower than faster ones.

How to use it

Silktide lists pages in a table, slowest pages first:

For each page, you can see:

• Magnifying glass – this opens the Inspector, which shows you technical details about that page and how to make it faster.
• Load time – how long that page took to fully load.
• Size – the size of the page, or how large all of the files that it uses are in total (uncompressed)