Why do title searches take so long?

I just did a title search on the word “adult” in IMHO within the last year. The board took over a minute to complete my search. What’s weirder is that I only came up with 7 or 8 results.

When you search, do you select “Show results as threads” or “Show results as posts” ? Show results as posts will take longer, because every post has a title; usually it is the same as the thread title, but the poster can change it, so each post must be searched.