I can't, because we do not have access to a busy board to test it on. It also depends greatly on the power of the server.
The mod performs 1 query per refresh cycle (beyond normal vB init queries obviously), and then calls showpost.php (see that file for number of queries it executes) for each new or edited post found.
It's really impossible for devs to answer "will this work on my forum" questions, so the best way to find out is to try it

It's not going to physically set your server on fire
PS: In your signature, it should probably be "
save bandwidth costs" and not "
safe bandwidth costs"
Fillip