Mobile and desktop pages
Silktide attempts to test a website on both mobile and desktop devices. If a website is limited to 100 pages, Silktide would test up to 100 desktop pages and 100 mobile pages.
This is usually what you would expect. It does mean that Silktide does, by one interpretation, download 200 pages to test 100 pages. This is because it has downloaded each page twice, on both mobile and desktop.
Frames and iframes
Silktide downloads frames and iframes, but considers each frame to be a separate page.
Silktide attempts to find the number of unique pages it has been limited to. Some badly behaved websites can produce an infinite amount of duplicate pages, redirections, or non-functioning URLs which would keep Silktide searching forever.
To prevent this, Silktide limits itself to 4 downloads per desired page. This means if you are testing up to 1,000 pages, Silktide will make up to 4,000 downloads before stopping automatically.
If your download limit is being reached, and not all of your desired pages are being found, you should consider defining rules to exclude specific URLs. If you are able to exclude sections of the site that are infinite, you should be able to stay within your download limit and find all of your real pages.