ok, so something strange was occuring with my original lsws directory to cause this to occur. i moved it to lsws.old then reinstalled from scratch, configured the admin, then shut it down. i cut and pasted just the virtual host entries from the config xml file and copied over the vhost files themselves (i put them in their own seperate dir)
It appears that all is well and the lsws server is rippin fast even without sendfile()! huzzah!
If you're having this issue, try doing the steps above... basically delete and reinstall. worked for me!