By default cache plugins will generate cache when the first visitor visits the page. Swift Performance provide more sophisticated solutions to optimize and generate cache for pages, to avoid slow pageload for first visitors.
Optimize Prebuild Only
If you enable it, Swift Performance will optimize pages and generate cache only if the prebuild bot visits the page. If a real visitor arrives to a non-cached page, it won’t trigger the cache generation, but load the original version for the visitor. It is always recommended to use this option, otherwise first user may wait even 30-40s until the optimization process finishes.
Optimize in Background
In rare cases Optimize Prebuild Only may will not be ideal for your site. In that case you can use Optimize in Background feature as a fallback. If visitor visits an uncached page, after it has been loaded, Swift Performance will start the optimization and caching in the background with an AJAX request.