Limit the MPD input buffer to less than the available memory.

[the_bertrum]

It does work in that it will get the whole of a track into memory at track change rather than get it in chunks as needed throughout the playback.

How does it behave when you have a whole rip in one flac and the tracks are just delimited with a CUE sheet?
Does it load the single FLAC chunk defining the track, or ill it attempt to load the whole FLAC at once?

No idea, but I suspect it works on files so it would be the entire FLAC file.  I don't have any suitable files to try it with.