Why does SharePoint Online take so long to load?
The article Navigation options for SharePoint Online shows an example of using the SPRequestDuration value to determine that the complicated structural navigation was causing the page to take a long time to process on the server.
How to tell if a file is loading in SharePoint Online?
By taking a value for a baseline site (without customization), it is possible to determine if any given file is taking a long time to load. The example used in Navigation options for SharePoint Online is the main .aspx file.
Is there an item limit on SharePoint lists?
If you’ve operated sites with SharePoint Lists or Libraries for any amount of time, you or one of your customers will trigger the Item Limit Threshold in a List or Library.
Is it possible to have a large SharePoint library?
Best practices and strategies for building and operating large SharePoint Lists and Libraries well above the item limit threshold List or Library above 5000 items is indeed possible with planning and some filtering/sorting compromises. If you can make it modern, you should. The modern experience improves over time; classic does not.
What should I do if my SharePoint website is slow?
Once you have identified that an issue specific to your site, the recommended way to figure out what is causing poor performance is to eliminate all of the possible causes, like page customizations, and then add them back to the site one by one.
When to use IIs to troubleshoot performance issues?
Before you begin, it is important to note that all fields IIS can log are not enabled by default. For example, Bytes Sent and Bytes Received are not selected, but they are very useful when troubleshooting a performance problem. Therefore, the best time to include these additional fields is before you are experiencing system problems.
How to fix performance issues in SharePoint Online?
In the F12 tools, on the Network tab, press the green play button to load a page. Click one of the .aspx files returned by the tool and then click DETAILS. Click Response headers. What’s causing performance issues in SharePoint Online?