OK, I've installed the latest version clean. Memory usage is less than 39MB, and all is well with the world. Then I mount one of the exported disks from this laptop running Linux. After a while the network traffic starts up, and memory usage starts ramping up at a rate of about 1MB/sec. Note that I haven't actually accessed the disks.
When I unmount the disk, network usage drops to nearly nothing, but the 1.5GB RAM for GWCtlSrv is only marginally reduced. Half an hour after the unmount it is still writing to the disk at a rate of over 2MB/sec.
I also mount these SMB disks from two other unix machines, but it appears that these machines are running an older version of Samba. These other machines do not caused this increased network traffic.
So anyway, you now have a way to test this for yourself. Access a Windoze disk from a machine running the latest version of Samba. I don't know if the machine has to be unix or not.