Improving SSHFS performance when reflecting changes in host directory
SSH is not designed to be a file transfer protocol. SSHFS works by periodically looking at the directory list and caching results.
You can control the caching behavior, but at the cost of performance as it relates to interactivity. If the SSH host you are connecting is accessed via a high latency link, or slow connection, then disabling caching is going to make things browsing the filesystem painful.
Anyway, see the man page, and experiement a bit.
man sshfs
-o cache=YESNO
enable caching {yes,no} (default: yes)
-o cache_timeout=N
sets timeout for caches in seconds (default: 20)
-o cache_X_timeout=N
sets timeout for {stat,dir,link} cache
Check that your host is in your /etc/hosts
file, this solved the overhead for me
Source: http://hints.macworld.com/article.php?story=20050329185832952