Performance Testing News for March 25, 2014

Browsing Over Top 50 Retailers in the UK

Intechnica has recently discussed with the top 50 retailers in the UK on the means and methods that can be adopted in improve performance of their online presence. Andy Still conducted an investigation using WebPageTest under normal traffic conditions and came up with the following observations:

Most follow general good practice
The majority of the companies were doing the obvious things (minifying javascript, compressing content, using a CDN etc). Besides a few exceptions, this illustrated that there was unlikely to be a simple, config based solution to the slowness.
Slowness was caused by client side, not server side, issues
None of the sites spent more than 0.5 seconds waiting for a server response, indicating that the server is not struggling to return content. This is as would be expected for a site homepage that is not under load.
Very large page weights – especially javascript
A large chunk of the slowness was being caused by the weight of the web page. All of these e-commerce sites were requesting well over 100 elements with some requesting over 200 items.
The largest portion of this was images. Most websites are heavily dependent on images to attract visitors. Some of these sites depend onhigh quality images as essential for business. It’s a good task to check if these websites were using compressed images.
From the slow slow loading sites was the general size and number of javascript files that were being requested. Websites were requesting over 40 distinct javascript files and file sizes totalling 300kb+ were common, with one site topping 600kb of javascript content. In most cases this javascript had already been minified and compressed. In all these cases the use of javascript should be fully investigated and rationalised.
to read more on the investigation visit Performance by Design