There is lot of documentation on best practices for SharePoint Online and how to optimize performance.

I'm looking for an exact description of how to create a brand new Modern Site that will perform as optimally as possible as a shared document library and for basic lists?

We don't really need anything else.

What configurations should I really be making? CDN? Publishing + Output Caching? Team Site vs Communication Site? Any Other stuff?

I'm looking for a single, clear configuration state, not a combination of optimization guides.


UPDATE: What would be really helpful is to understand if there is a definitive answer between what's faster: - Communication Sites - Root Modern Team Sites - Modern Team Sub-Sites (with no O365 group, as created from an existing site)

Also, it does seem that I am able to enable publishing on a new Modern Team Site and then enable Output Caching - any idea why/how if it's not supported?

Regarding the CDN advice - is this to say that there is no value in enabling the O365 tenant CDNs as advised in some of the "performance tuning" articles MS provides?

2 Answers 2


Is this for largely read-only content like the HR site or a site with lots of user uploads and edits? You need to tell us a bit more about how these sites will be used.

There is no "exact description".

As you are asking about Modern UI sites, there's little customization you can do.

  • Publishing features are not supported in the Modern UI (at least not yet), so page caching is not an option.
  • In SharePoint Online you are a "tenant" and have little control, especially in the Modern UI, for how the pages work.
  • Microsoft already maintains their own CDNs for much of the default SharePoint content, such as images, JavaScript libraries, etc. So, not much you can do there.
  • Placing any large images you might display on the home page in a CDN, possibly in Azure, may help. Avoid storing images or other frequently linked content in libraries.
  • Don't use themes with background images. Keep it simple.
  • Minimize the amount of active content on the home page. I.e. use static content and no, or few, web parts.
  • Modern Team Site vs Communication Site is more about the intended use of the site. Team Sites use Modern permissions and can support classic permissions while Communication Sites still use only classic permissions. (This could let you add most of your visitors as read-only users.)
  • Add indexes to frequently sorted and filtered columns. (SharePoint Online will do this automatically as needed.)
  • Minimize lookup columns.
  • Avoid custom "anything". Stay as out-of-the-box as possible.
  • Communicate with Microsoft about any performance issues you are having.
  • Where you can, improve bandwidth and network performance for your users.

In the end, most of the things that could tweak site performance are outside of your reach as a SharePoint Online tenant.

Microsoft's guidance is here: https://docs.microsoft.com/en-us/office365/enterprise/tune-sharepoint-online-performance


It really depends on what you are allowed to do. Are you the head site collection admin? Can you turn off site collection features? Can you edit the master page?

As Mike Smith stated, you do not control most of the problems with speed when using SP Online.

Options you might be able to control:

  1. Bring the site in-house on your own SP servers.
  2. Don't add any extra css files. MS css is bad enough don't make it worse.
  3. Turn off the site collection feature MDS. It is designed to make page loads faster by only loading the changes. If it hiccups, it just loads the whole page over. So you end up loading a part of the page, hiccuping, and then the whole page.
  4. Find/make a speedy master page. The default master page has code for everything anyone might do. Get one that only has code for the few things you want to do.

  5. Get Microsoft to fix the core15.css. The bloat is horrible.

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