Space Page Loading Slow - Recent Posts Causing Problem - Suggestions?

In terms of performance troubleshooting will be interesting to know IF the OA web site deployment was made externally (using a Web Hosting compatible platform) and you're just accessing it (uploading to/downloading from) over the Internet or IF the OA web site access is done locally in a defined LAN environment (Web Site server and clients belong to the same LAN segment or they're managed by the same Firewall in case of multiple subnets scenario), the latter has symmetrical higher bandwidth and very low delay compared to accessing over the Internet so accessing locally stored media contents should have little impact from user perspective (if the OA deployment was done properly).

I had a user that uploaded, like it used to do when working with a shared Network Folder, about 250 pictures (just about 600 MBytes) into a Files Section (under a single Folder) thinking that, doing so, he would be able to see those pictures in thumbnails has happens when working with shared Network Folder using usual network access methods (SMB, NFS, AFP, etc.)...which, I know yet, didn't happened in that specific Section type.

So, sooner or later, I will expect someone will ask me to show them through the usage of thumbnails...so I'm too interested in knowing how eventually a Discussion Post (*) with an attached Media Gallery Paragraph linking to that set of pictures (or just part of it) will behave when all (or part of) those pictures will be showed...I admit I've still to test it (this despite my Open Atrium deployment and access is LAN only).

(*) a Discussion Post or other content type for which an added Media Gallery Paragraph is the best way to show selected pictures in thumbnails.

The Recent Activity view tries to render the body of the node to be shown if you expand the line in the recent activity by clicking on it. The site has no way to know what might be in this body field. If the summary contains a bunch of large embedded images then yes, it's going to be slow. Since the Recent Activity is just a simple View, it doesn't have the ability to load the summary "on demand". We have considered writing another Angular App for this kind of display where we would have full control over the ajax etc, but then we'd lose the ability for site builders to customize the view.

The way the Recent Activity is rendered is actually controlled by the Message templates. Each line in the view is a Message, such as "content created..." or "content updated...". If you go to Admin->Structure->Message Types and look at one of the messages (Edit), you'll see different View Modes for different things, such as email notification subject and body. You'll also see View modes for the "River" (Recent Activity stream) Header and Body. You should see a token like [message:field-oa-node-ref:body] which embeds the body of the referenced node.

If you remove this token from the River Body and River Accordion then it will no longer render the body of the node and will improve your performance. Of course, this will cause the oa_messages feature to become "overridden" so you might need help to get this change into code so you don't lose it during an upgrade.

There is also a distinction between embedding images in the Body field via the WYSIWYG vs adding them using the Related Content Media Gallery or putting them into the attachments. If you can convince people to start using the Media Gallery paragraph for images rather than the WYSIWYG embed then you won't have these issues. Then the images will show up in the thumbnail view on the right of the node, and you'll get access security for the images.