Question
Why does the onpage analysis take so long?
Answer
The crawl delay can be set for each onpage analysis in the advanced settings of an onpage analysis. This is the time that the crawler "sleeps" after each page request.
The Crawl-delay property can also be set in Robots.txt - this has the same effect as described in point 1, except that this works for all XOVI crawls (provided it is set for the correct user agent).