The "all websites dashboard" is slow

I’m using server logs and not the Javascript method. The logs are parsed and processed once a day at midnight. I’ve turned off “archive reports when viewed from the browser” option in the settings, and I’ve set “browser_archiving_disabled_enforce = 1” in the “general” section of the config file.

When I open the “all websites dashboard” for a new date range, it takes about 20 to 25 seconds to load.
When I open a date range, it seems to be cached, and from that moment on, it can be opened immediately in all browsers and devices. If I change it to another range that was not viewed before, it needs another 20 to 25 seconds.

I’ve not ran into a similar problem in any page other than the dashboard.

Is it normal, or can I expect a faster dashboard?