Please see the following FAQ entry, while this FAQ entry deals with slow uploads the same can sometimes apply to downloads as well under some conditions.
https://oss.azurewebsites.net/forum/flashf...indows-xp.html
In your case instead of changing the send buffer size you'd want to try experimenting with the receive buffer size.
FlashFXP is capable of downloading at a high rate of speed but there are several factors that can impact performance.
As far as FlashFXP settings go this is the only setting that will have any impact on performance.
Other possible factors include but not limited to software based firewalls, Windows network configuration, the network card and/or driver configuration, local network (wired and wireless) routers and the way they're configured.
Sometimes high packet loss and/or latency can result in reduced transfer speed, this is especially true if windows is configured with TCP window scaling disabled. (
http://en.wikipedia.org/wiki/TCP_window_scale_option)
