I searched for both “headers” and “titles” in ATMB and didn’t find this, so I thought I would share a discovery. You can click the headers — Thread, Thread Starter, Replies, Views, Last Post — within a forum to sort threads in ascending or descending order by the relevant column. Because these fields are indexed, the resulting display is fast and puts no more load on the SQL server than simply opening a forum.
Excellent! Thanks for this.
Are you sure it doesn’t add any strain?
When you go to a forum’s main page (and you have it set for the past two days, for example), only the first page of that two-day result is shown. In ATMB, there would likely be only one page, but in MPSIMS, there might be many more.
So when it displays only the first of several pages, does that mean it’s already downloaded the other pages - it just hasn’t yet displayed them?
So if they’ve been downloaded already, then it’s just a matter of you paging through them - and that’s not adding strain, because the pages have already been retrieved from the server. Then when you do a sort on any of those columns you’re basically sorting on what’s already been retrieved - hence, no added strain.
On the other hand, what if the threads are retrieved from the server on a page-by-page basis? That would mean that when you visited the main page, the system retrieved only enough threads to fit on that first page of threads. Then when you wanted page 2, it performed a second retrieval, and so on.
If this is true, then when you sort by column from the main page, the system would have to do an additional retrieval to obtain all of the threads that didn’t make it on the first page.
This is all so confusing…
Relax. You’re a wigwam and a teepee. 
On the forum page, the server does not retrieve “pages” at all, but merely strings of data to fill the table that lists the threads. Whether you accept the default sorting or sort by the headers, the exact same amount of data is returned.
It’s really exactly the same as using the drop-down lists at the bottom of the forum page, only a bit simpler.