When saving an updated node, does the update operation clear all caches?
There is only one line about clearing cache in node_save():

// Clear the static loading cache.
entity_get_controller('node')-&gt;resetCache(array($node-&gt;nid));


It only resets entity-related cache. Caches related to another nodes, caches like boost and so on are left untouched, unless specifically cleared by other module's actions in node or entity saving hooks.