I think you are missing the point. Matt was agreeing with my assessment of the situation. He was only stating I told you the wrong setting to change. The setting to "play from memory" is not for fixing network hickups. It is for audiophiles who believe they can hear the judder when the playback stops then jumps forward for 1/10,000th of a second...
All joking aside though you are not using it as it is intended. It is supposed to read in the entire file into memory. What you are reporting is the exactly the way it is was designed to be.
If the pre-buffering setting is not working, you likely have other issues at play. I can easilly playback 200MB 24/96 Flac file over my 100Mbs network with the default pre-buffer setting. If you have Gigabit and things are jamming up, you have either network or local computer problems that are causing the issue.
If you are trying to stream over wireless, that is no surprise. Wireless doesn't work well for streaming except under perfect conditions. You need 802.11n based network for starters and placement of the access point and wireless card can have a big effect on speed. I would try transfering a file using windows and see what kid of speeds you get.