Page is a not externally linkable
-- Google SEO News and Discussion
---- Big traffic loss after my page speed dropped
dstiles - 7:46 pm on Aug 31, 2011 (gmt 0)Thread source:: http://www.webmasterworld.com/google/4357042.htm
My guess would be that bots got rejected along with customers. Slowing down a site isn't just slower delivery. Check the number of 500's in your stats (may be a different number but probably in the 5xx range).
Brought to you by WebmasterWorld: http://www.webmasterworld.com