The holdup was a 20 second delay per request from the a bug in the Zend Framework (not officially described as a bug yet).
Everything seems to be fast now!
I still need to connect the adapter which will send the Drupal data to Sesame.
I've created a patch to the Zend Framework here (one line).
The patch is here http://semanticsearch.org/patch-zend-framework-socket-php-http-client
I documented the process here
http://www.openrdf.org/forum/mvnforum/viewthread?thread=1417