5 Factors Affecting Website Performance

Strong website performance is a cornerstone of any successful website because first impressions matter. How long would you wait for a website to load? According to Google, 53% of Visits are abandoned if a mobile site takes longer than 3 seconds to load - which is a big problem.

To improve website performance, you first need to identify what is slowing your site down and what you can optimise to speed things up.

What is website performance?

Website performance measures how quickly the pages of a website load are delivered and displayed in a web browser. It is also important to consider this from a User Experience (UX) perspective. How fast does the website feel to your users?

We can look at time in two different ways: objectively and psychologically. Objective time is time measured in intervals on a clock, indicating the duration between two events, for example clicking on a website link and the website loading. This objective time is usually different from how users perceive time when waiting - this is psychological time. Think; a watched kettle never boils.

Although perceived performance is a purely subjective measure of website performance, it is perhaps even more important than the actual speed of operation. Why? Simply put, slow websites freak users out.

Slow websites are stressful to users

It has been reported that website loading delays lead to a 38% increase in heart rate, on average. These levels of stress are comparable to watching a horror movie. So, unless you are running a Wes Craven fan site, this is not the way we want visitors to feel when using our websites.

How fast should a website load?

According to Google, 53% of Visits are abandoned if a mobile site takes longer than 3 seconds to load. A recent study by backlinko that analysed 5.2 million desktop and mobile pages revealed that the average page loading speed for a web page is 10.3 seconds on desktop and a whopping 27.3 seconds on mobile.

It is evident that there is a lot of room for improvement. Google incentivises us to improve website speed with the lure of ranking highly on their search engine.

So to answer the question, how fast should a website load?; Ideally a website should load as fast as possible. See below comment by a Reddit user on r/bigseo for a useful visual guide:

Page speed & SEO

Speed has been a ranking factor for Google from as far back as 2010 - and they have been preaching the importance of site speed ever since. The latest update on site speed as a ranking factor came in mid-June 2021 when Google rolled out the Core Web Vitals.

The Core Web Vitals is a UX-focused algorithm, consisting of three metrics (FCP, FID and CLS) that measure the load time, interactivity and visual stability of a page. These metrics are a way to signal perceived performance and they apparently play a role in organic ranking as part of Google’s page experience signals.

However, after less than a year of core web vitals it is still unclear how much of an impact this update has had on organic ranking. Ultimately it seems that great content still takes precedence over speed and UX as summarised in the below quote:

“In general, we (Google) prioritize pages with the best information overall even if some aspects of page experience are sub-par. A good page experience doesn’t override having great, relevant content”.

John Mueller – Search Advocate at Google

Rankings aside, improving website speed is still of huge importance as any visitor that leaves a site, or doesn’t go on to convert due to poor page speed is a potential customer lost.

How to tell if visitors are leaving your site

Slow websites will typically have a high bounce rate, which is a deceptive marketing term that kind of sounds fun—but trust us—it is not. Bounce rate relates to the percentage of single-engagement to your site. Google Analytics tracks the number of people who visit your page and leave without viewing other pages on your site.

You can monitor bounce rate in Google Analytics (or similar metric tracker), and use PageSpeed Insights to find out ways to improve your speed.

The good news is that improving your site speed has been proven to decrease high bounce rate. A study by 55 & Deloitte found that a mobile speed improvement of just 0.1 second for an informational page decreased bounce rate by 8.3% for 1 in 2 lead generation sites.

It is critical to consider the context around bounce rate to get a full picture of what is actually going on. If you’re running paid advertising campaigns, you can generally expect this traffic to increase your bounce rate, especially if you’re sending traffic to a dedicated landing page built for paid campaigns.

By design, users on these pages will usually have 1 of 2 options - convert through your CTA, or bounce.

Display traffic is also likely to be bouncier than Search traffic as it’s more prospective. The user isn’t searching for a specific query to be shown an ad, but instead they’re being targeted through their interests, demographics, retargeting lists etc., which can cause bounces.

Additionally, bounce rates vary massively from industry to industry.

Bear in mind the context of your bounce rate (what traffic source it’s coming from, what pages it’s happening on…) before you look at this as a metric to improve through site speed optimisations.

So, in the context of slow website speed bounce rates are a red flag. But on the flip side it can be used as a KPI to track improvements from website speed optmisations.

What factors affect website performance?

There are many factors that make up a successful website, most of which affect website performance. We’ve highlighted 5 factors affecting website performance, and a few ways to improve them.

Images & file size

Large images slow down your web pages which creates a poor user experience. Optimising images is the process of reducing their file size, using either a plugin or script, which will speed up the load time of the page.

Striking a balance between pages that need more impact (such as a homepage) and those that require optimum performance (like a PPC landing page) is a good strategy for reducing too many image heavy pages. A single page of plain text could take up as little as 4KB of space. A full-page image is more likely to take up 80KB to 100KB even if properly optimised.

Using the right file formats ensures that images are optimised. A good rule of thumb for basic image file formats is:

• JPG - real life images
• PNG - graphics, charts, non-photographer images

Server/Hosting

The website hosting provider that you choose can have a huge impact on your website’s performance. The plan you choose is also important, for example, many small business owners choose to go with a shared hosting plan –which is a server that hosts multiple websites.

This is a fine choice if you anticipate less than 1,000 visitors per day. Resources such as disk space, CPU, and memory are shared, and costs are split between all the users on that server. Which is a great cost saving arrangement.

But if you have a thriving online business that attracts a large amount of traffic or your website requires a lot of data for things like streaming videos or custom apps, a shared host isn’t going to cut it. The limited bandwidth and RAM will cause your site’s performance to suffer. Causing visitors to have a poor experience.

Code

Bad code can take many forms—from Javascript errors to invalid HTML markup— it can all cause significant dips in performance. Superfluous code is code that is poorly optimised, adding extra lines that do not add meaningful value, functionality or substance to a website.

To ensure your code is well-structured, seek out an agency with broad technical expertise as they can build your website in the most efficient way possible to make performance a priority.

Common technical issues that we see on many websites are broken and uncompressed Javascript and CSS files. Oftentimes these issues can be caused by third party code, or can be simple fixes.

Browser caching

Caching is the holding of data in memory to increase performance. Web applications can keep high-priority data in memory so that it can be processed more quickly.

The data held in memory acts as a ‘snapshot’ of a website which can be served quickly upon request. Leveraging browser caching is a great way to speed things up on your site.

HTTP requests

Every website uses the Hypertext Transfer Protocol (HTTP). For a website to load in a web browser, the browser must first send an HTTP request to the website’s hosting server. Then the server sends back the requested resource.

Each resource request decreases page load speed, so the fewer requests you have, the better your site will perform.

Essentially HTTP acts as the middleman and interpreter, acting in the background to enable & improve communication between client and server. There are a bunch of HTTP status codes–a 3-digit code–that is sent every time you request a web page. The more files you have the more HTTP requests you will have and the bigger those files are the longer those requests are.

Say no to slow websites

Speed and performance are vital to your website’s success. Improving website performance is a lifelong journey for most SEO, marketing and development folk.

We’re constantly looking for ways to improve site performance, keeping up to date with the constantly changing algorithms to create better sites, experiences and content.

Is your website underperforming? Maybe it's time to shake things up. Get in touch to discuss your website redesign.