Slow to load certain pages

I’ve used the MediaWiki XML extension to import roughly 1200 pages into my wiki. I have them all organized properly and everything looks great; however, the more I use it I find that some pages take a couple seconds to load, while some load instantly. Its weird because the pages that take a while to load will only take a while to load on the first access. After the initial access the pages are loading instantly. I’ve checked the MySQL logs and there are no errors and the queries occur in less then a second. Any ideas?