Why is my SharePoint page slow to respond? There are many factors that can impact page performance including the elements that make up the page, network performance and the device you are accessing SharePoint form. While we might want to blame DNS, it is usually not to blame in this case!

The SharePoint Site Performance tool is a good place to start. Access is via the Settings Cog and requires the installation of an Edge or Chrome extension.

The first time you choose this option, you will be prompted to install the a browser extension.

Go to the page that you want to check and run the Page diagnostics for SharePoint extension by clicking the extensions icon at the top right of your browser.

Optionally click the export to HAR option if you want to save the data. Click Start. The process can will automatically reload the page and capture data. Once it completes you can see details of the page load and all of the elements that make up a page. This is similar to the browser diagnotics tools but with more SharePoint specific detail.

You can access the most recent performance data by adding “_layouts/15/score.aspx” to the end of your page URL

In this example you can see my page performance is good, but there is a large image that is slow to load. The full report gives details on items that are slow to load or run and suggestions how to improve them. It also lists items that are performing well.

So what can make your site go slow? Many things, but here are some of the common things I have seen.

• Webparts that search large amounts of data every time the page loads.
• Lots of large images.
• Views that return a lot of items e.g. when the row limit is increased from the default 30 items.
• Custom webparts or javascript code.
• API calls to other systems where the response time is slow.
• The Viva Engage (Yammer) webpart can be slow to open.
• Lots of webparts, especially search based ones like News and Events.
• PowerApps on a page can be slow to open.
• Slow internet connections.
• Lower spec devices e.g. cheap tablets and older PC’s with low end CPU’s and little available memory

Slow performance can be hard to diagnose. How do you know if the issue is a page or SharePoint in general? Test a page with minimal content e.g. just a text webpart and compare it. If the minimal page is slow, it might point to something else in the environment rather than the page, however if the minimal page is fast, then you should look at the page diagnostics for insights as to why.

Resources:

Diagnosing Performance Issues with SharePoint

Optimising Custom SPFx Webpart Performance

Optimising Edge performance in VDI environments