FTP slow with FasTrack enabled on MyNet n900

Short Version:  Enabling FasTrack QoS slows down regular FTP traffic (up or down) from about 800 KB/sec to about 60 KB/sec.

Long Version:

I noticed tonight while trying to upload (or download) a 3 MB file to my web hosting server using FileZilla FTP that it was quite slow – about 66 KB/sec either way.   I duplicated the experience in WinSCP so I knew it wasn’t just FileZilla.  I then figured out that if I connected via SFTP instead of plain FTP, it was faster – about 800 KB/sec average.  

I wondered about my server but also took a look at my router settings in the meantime.   Just for kicks, I tried disabling the  FasTrack feature and regular FTP sped up to about 1 MB/sec up and down.  I re-enabled FasTrack and it slowed back down to 60 KB/sec or so.  Disabled it again and it was fast again.  So for some reason it seems evident that FasTrack slows down regular FTP (but not SFTP) when enabled.

Why does this happen?

Thanks!

Firmware Version: 1.06.18

Firmware Build Date: Fri  21  Dec  2012 

What’s your downlink and uplink rates from your ISP? 800KB/s up = 6.40Mb/s up. I think FasTrack is only enabled if your uplink is no more than 2Mbps. When it’s turned on, what is the auto detected uplink speed? Did you try manually setting the value to your subscribed uplink speed?

I have this same problem.  Recently, after the firmware update around dec. 2012 or so, I noticed filezilla download / upload speed was severly limited.  I would normally upload around 120 KB/sec and download around 1600 KB/sec.  Now, I can only get 50 KB / sec max no matter up or down. Plus it seems to pulsate.  

I can logon to the same server via a web file manager and download at 1600 KB/sec again.  Just not via ftp.  This is a real bummer.  And I would love to know how to fix it.