haven't tried beta 2 and 3 because beta 5.0.1 was slow, too.
now i've tried 5.0.4 beta and all works fine. got full uploadspeed!
problem seems to be solved!
See https://winscp.net/tracker/690
Before posting, please read how to report bug or request support effectively.
Bug reports without an attached log file are usually useless.
haven't tried beta 2 and 3 because beta 5.0.1 was slow, too.
now i've tried 5.0.4 beta and all works fine. got full uploadspeed!
problem seems to be solved!
Bug 677 is listed as fixed in 4.3.3, so do you mean that the fix is what is causing the problem?