I was interested to find the I/O performance of the Pi when writing to different media: USB stick, SD card, Windows share. I wrote a program in C that creates a 100MiB file and then ran it and recorded its times with the time command. Since the Pi's Ethernet port runs at 100Mb, I wouldn't have expected any better performance than the 8.3MiB/s achieved.
|Media||Real (Elapsed) time||User time||System time||Transfer Rate|
|Network share (cable)||12.03s||0.38s||3.37s||8.3MiB/s|
|Network share (WiFi)||44.88s||0.36s||3.96s||2.2MiB/s|
|USB - TDK 4GB||14.68s||0.73s||1.38s||6.8MiB/s|