Browser download speed numbers are very unreliable because after you click on a link, while you are selecting if you want to open or save and where to save, browser is downloading in the background. so once you click on OK, it instantaneously jumps from 0 to whatever is downloaded up to that point, which skews transfer speed. if you want more accurate numbers, download wget from
http://www.christopherlewis.com/WGet/WGetFiles.htm and use it to give you more accurate transfer speeds.
Regarding FlashFXP
1)upgrade to the newest build, 1220 is old
2)F6, Connection, tcp/ip buffer size. change those values, restart flashfxp and see transfer speed. largest or smallest numbers are not necessarily the best.