We've noticed a big drop in the total pages crawled per day on our site, we have no control over the crawl rate in google webmaster tools so it's possible this has been changed by google. However it's a fairly large site and I wouldn't of thought that the crawl rate would've been decreased.

What we have noticed though is a sizeable increase in page load times, in my mind this would be the cause. Can anyone else confirm if the crawl rate is directly correlated to page load time? Seems logical, longer page load time, less pages crawled.

Any decent documentation on this would be appreciated, I don't normally have any input on SEO so this is new to me.