During my download manager development I tried a number of different methods to download files. This article was invaluable, as it explains how to download in 50k chunks rather than buffering much larger amounts.

To start with a tried buffering about 5mb. Seemed sensible, since I figured it would cut the amount of writing to disk that would required. Especially since most mp3 files are about that size. Unfortunately it did not work, since for some reason downloaded files were becoming corrupted. 50k is a pretty good level of buffering to improve performance and avoid an infinite level of disk reads.

For a while I figured that changing the method for downloading was impacting performance due to the application hanging and scrolling being disabled. This was due to an unnecessary amount of debugging though. Or rather - writing out to a text field for the purpose of debugging without relying on trace statements.