Lackluster AWS file transfer speed?

Using Advanced Web Server to send a file of any size, I see 400 KB/s or 3% bandwidth maximum on a isolated/quiet 100 Mb/s Ethernet using a NET+ARM 50. What can be done to increase this to something more in line with a 100 Mb/s Ethernet connection? Even with a UDP bulk transfer kicked off from the AWS CGI, I only see a marginal increase to about 500 KB/s to 600 KB/s. rp03