Activity menu item very slow

I have set up an Activitry menu item using the defaults, nothing changed on the 'Activity' tab.

When it is clicked, the page load takes around 31 seconds which is a very long time.
I had emptied the table and there are only 161 rows at the moment.
The rest of the site runs well; we are on a dedicated server with Easyspace.

The only activities being recorded are image related for now.

Have you any ideas why the page load should be so slow?

It is fast if I empty the table again and have only ten rows

Please ensure you've latest CB Activity 4.2.0 installed as significant performance improvements have been made. As for why it's loading slow for you my best guess is you've adjusted the paging parameters and maybe are trying to load your entire database worth of activity on a single page. Ensure within CB Activity > Parameters > Activity > Paging you've a reasonable value set for "Page First Limit" and "Page Limit".