I noticed a huge performance drop in a site that I run, after me and my colleagues digged into the cause we found that the filefield widget array in _content_type_info() contained over 260,000+ blank items. This was then repeated another 2 times in the cache blob.
What could cause all these extra array items? It's causing a huge performance loss and out of memory errors when drupal tries to unserialise the content.
We posted here http://drupal.org/node/1009596 and narrowed it down to filefield.
Any help would be great.