OpenBSD, ctorrrent & Funes

I don't get this... The memory usage of OpenBSD seems really bizarre.
I have installed 4.2 on a plain vanilla crap box. (an Intel Celeron @268MHz, 128 MB RAM & a couple of IDE drives), enabled MRTG & SNMP to poll data to graph trends on the hdd use, load, etc. (link).
Everything is fine & peachy; but, these last days I have been downloading a few torrents, and I noticed that the more stuff that ctorrent pulls thru the ethernet interface, the lesser the memory use...


The ethernet card use starts to build up as the Torrent runs for a while.

And the RAM usage drops accordingly...