Is it actually the smartermail service or the IIS web interface that actually is hanging?

 

Check your logs, I doubt it has anything to do with your memory given your stats.

K Soon, another question to ask is if you are using a 32-bit or 64-bit server.  A 32-bit server will only utilize around 1.3 GB of memory for an app even though your system may have more system memory available.  If that "magic" number of 1.3 GB is reached, the app may become unresponsive.

Guess I just can't no satisfaction.. (or in this case response...)

This was the same issue I ran into over the weekend
( Please refer to :http://portal.smartertools.com/community/a2738/server-load.aspx )

 

We are running 64bit server.  It was NOT IIS that spinning out .. but SM service itself.
It occurred on Sunday.. without any 'load' or hardly any traffic  (you can read the post).
I was looking for a memory setting to control how much it used.. because it can kept climbing.

It spun out twice.. but hasn't repeated since then (of course it is only Weds.  :)