Could drush require significantly more memory than same action in Drupal I am running Drupal 7.23 and drush 5.9

I can clear all caches in Drupal without an error but get "memory exhausted" if I try using drush cc all. I get "memory exhausted" when using "drush up", after it has downloaded and updated modules but was able to download and update the modules from within Drupal.

Is there anything that might be leading to a greater need for memory when using drush?
Probably not - but remember that in PHP 5, the command line or client interface for PHP was separated out and has its own ini file. if you search for your php.ini file, you'll probably see two versions, something like this

/etc/php5/cli/php.ini
/etc/php5/apache/php.ini


and you just need to match the memory limit in the (cli)ent ini file with what you have for Apache (or your web server).