Hmm that's curious. FlashFXP can't identify my current send buffer size, which makes me wonder if it's still set to 1 kB after all this time. I used to know which setting it was, but not any more. I've got this:
SPS=8
RPS=17
But my receive buffer is 128 KB. There's also:
CB6=128
...
CB10=128
But it's not either of those. Nothing else in FlashFXP has "128" in it. I don't think we're ever meant to touch the INI file
Whatever I did set the buffer size to (!) it's obviously not helping. One factor that does come into play though is (obviously) RTT -- an upload to a site more local to me is making the Web not quite as slow. This FTP site is extremely responsive, while most FTP sites -- all on the far side of the Atlantic, if not the far side of the US on the far side of the Atlantic -- tend to crawl a bit (think of connecting when the server and client chat for a while).
I guess TRWTF is the Windows packet scheduler.