Transfer speeds decrease rapidly during operation

For the past few days there have been rapid decreases of transfer speed when downloading or uploading files. For example, when I start the transfers (uploading files for a forum), the speed starts out around 30kBps, and within a few minutes drops to 1.4 or less! I've seen it go as low as 0.08, which is quite useless by then. It might be coincidence but it seems to happen with image files (png, jpg, gif, etc.) more than other file types.

I'm using Windows 7 64-bit, my firewall and AV are not holding anything back, and my ISP is clear. I've tried uploading to 3 different servers of 3 different web design clients, and it's always the same result, so I know it's not a remote server issue.

Any ideas?

Does the transfer of small files time out after a while? Check the transfer log and post it here.

I'm not sure that file size is a factor more than the file type. There are various sizes of files, and the only ones that give me a problem are images, big or small. But looking at the log it seems to have totally quit on me now.



Private data replaced with dummy text...

[19:11:17] SmartFTP v4.0.1140.0

[19:11:20] Resolving host name "sitename.com"

[19:11:20] Connecting to xxx.xx.xxx.xx Port: 21

[19:11:20] Connected to sitename.com.

[19:11:20] 220---------- Welcome to Pure-FTPd [privsep] [TLS] ----------

[19:11:20] 220-You are user number 1 of 50 allowed.

[19:11:20] 220-Local time is now 18:11. Server port: 21.

[19:11:20] 220-This is a private system - No anonymous login

[19:11:20] 220-IPv6 connections are also welcome on this server.

[19:11:20] 220 You will be disconnected after 15 minutes of inactivity.

[19:11:20] USER username@sitename.com

[19:11:20] 331 User username@sitename.com OK. Password required

[19:11:20] PASS (hidden)

[19:11:21] 230-User username@sitename.com has group access to:  groupname  

[19:11:21] 230 OK. Current restricted directory is /

[19:11:21] SYST

[19:11:21] 215 UNIX Type: L8

[19:11:21] Detected Server Type: UNIX

[19:11:21] RTT: 86.159 ms

[19:11:21] FEAT

[19:11:21] 211-Extensions supported:

[19:11:21]  EPRT

[19:11:21]  IDLE

[19:11:21]  MDTM

[19:11:21]  SIZE

[19:11:21]  REST STREAM

[19:11:21]  MLST type*;size*;sizd*;modify*;UNIX.mode*;UNIX.uid*;UNIX.gid*;unique*;

[19:11:21]  MLSD

[19:11:21]  AUTH TLS

[19:11:21]  PBSZ

[19:11:21]  PROT

[19:11:21]  ESTA

[19:11:21]  PASV

[19:11:21]  EPSV

[19:11:21]  SPSV

[19:11:21]  ESTP

[19:11:21] 211 End.

[19:11:21] Detected Server Software: PureFTPd

[19:11:21] PWD

[19:11:21] 257 "/" is your current location

[19:11:21] CWD /simpleblue/statusicon

[19:11:21] 250 OK. Current directory is /simpleblue/statusicon

[19:11:21] PWD

[19:11:21] 257 "/simpleblue/statusicon" is your current location

[19:11:21] TYPE A

[19:11:21] 200 TYPE is now ASCII

[19:11:21] PASV

[19:11:21] 227 Entering Passive Mode (xxx,xx,xxx,xx,122,130)

[19:11:21] Opening data connection to xxx.xx.xx.xx Port: 31362

[19:11:21] MLSD

[19:11:22] 150 Accepted data connection

[19:11:22] 226-Options: -a -l 

[19:11:22] 226 47 matches total

[19:11:22] 5666 bytes transferred. (19.7 KB/s) (280 ms)

[19:11:41] CWD /simpleblue

[19:11:42] 250 OK. Current directory is /simpleblue

[19:11:42] PWD

[19:11:42] 257 "/simpleblue" is your current location

[19:11:42] PASV

[19:11:42] 227 Entering Passive Mode (xxx,xx,xxx,xx,119,107)

[19:11:42] Opening data connection to xxx.xx.xx.xx Port: 30571

[19:11:42] MLSD

[19:11:42] 150 Accepted data connection

[19:11:43] 226-Options: -a -l 

[19:11:43] 226 12 matches total

[19:11:43] 1344 bytes transferred. (852 bytes/s) (00:00:01)

[19:11:52] CWD /

[19:11:52] 250 OK. Current directory is /

[19:11:52] PWD

[19:11:52] 257 "/" is your current location

[19:11:52] PASV

[19:11:52] 227 Entering Passive Mode (xxx,xx,xxx,xx,131,60)

[19:11:52] Opening data connection to xxx.xx.xx.xx Port: 33596

[19:11:52] MLSD

[19:11:53] 150 Accepted data connection

[19:11:53] 226-Options: -a -l 

[19:11:53] 226 286 matches total

[19:11:53] 33704 bytes transferred. (40.5 KB/s) (811 ms)

[19:11:56] CWD /bafdev

[19:11:56] 250 OK. Current directory is /bafdev

[19:11:56] PWD

[19:11:56] 257 "/bafdev" is your current location

[19:11:56] PASV

[19:11:56] 227 Entering Passive Mode (xxx,xx,xxx,xx,127,62)

[19:11:56] Opening data connection to xxx.xx.xx.xx Port: 32574

[19:11:56] MLSD

[19:11:56] 150 Accepted data connection

[19:11:57] 34102 bytes transferred. (47.4 KB/s) (702 ms)

[19:11:57] 226-Options: -a -l 

[19:11:57] 226 289 matches total

[19:12:22] CWD /bafdev/install

[19:12:22] 250 OK. Current directory is /bafdev/install

[19:12:22] PWD

[19:12:22] 257 "/bafdev/install" is your current location

[19:12:22] PASV

[19:12:22] 227 Entering Passive Mode (xxx,xx,xxx,xx,121,139)

[19:12:22] Opening data connection to xxx.xx.xx.xx Port: 31115

[19:12:22] MLSD

[19:12:22] 150 Accepted data connection

[19:12:22] 11886 bytes transferred. (27.5 KB/s) (421 ms)

[19:12:22] 226-Options: -a -l 

[19:12:22] 226 98 matches total

[19:12:42] MLST cmsdefaultdata

[19:12:42] 250-Begin

[19:12:42]  type=dir;sizd=2048;modify=20101021205625;UNIX.mode=0755;UNIX.uid=639;UNIX.gid=642;unique=c3g121cc03c; cmsdefaultdata

[19:12:42] 250 End.

[19:12:45] CWD /bafdev/install/cmsdefaultdata

[19:12:45] 250 OK. Current directory is /bafdev/install/cmsdefaultdata

[19:12:45] PWD

[19:12:45] 257 "/bafdev/install/cmsdefaultdata" is your current location

[19:12:45] MLST attachments

[19:12:46] 250-Begin

[19:12:46]  type=dir;sizd=2048;modify=20101021220927;UNIX.mode=0755;UNIX.uid=639;UNIX.gid=642;unique=c3g121cc03d; attachments

[19:12:46] 250 End.

[19:12:46] CWD /bafdev/install/cmsdefaultdata/attachments

[19:12:46] 250 OK. Current directory is /bafdev/install/cmsdefaultdata/attachments

[19:12:46] PWD

[19:12:46] 257 "/bafdev/install/cmsdefaultdata/attachments" is your current location

[19:12:46] MLST 37236.jpg

[19:12:46] 250-Begin

[19:12:46]  type=file;size=19833;modify=20101021220327;UNIX.mode=0644;UNIX.uid=639;UNIX.gid=642;unique=c3g121cc0eb; 37236.jpg

[19:12:46] 250 End.

[19:12:49] The operation has been added to the Transfer Queue. Check the Transfer Queue for the status.

[19:13:16] CWD /bafdev/install

[19:13:16] 250 OK. Current directory is /bafdev/install

[19:13:16] PWD

[19:13:16] 257 "/bafdev/install" is your current location

[19:13:16] NOOP

[19:13:17] 200 Zzz...

[19:13:47] NOOP

[19:13:47] 200 Zzz...

[19:14:18] NOOP

[19:14:18] 200 Zzz...

[19:14:48] NOOP

[19:14:48] 200 Zzz...

[19:15:19] NOOP

[19:15:19] 200 Zzz...

[19:15:49] NOOP

[19:15:49] 200 Zzz...

[19:16:20] NOOP

[19:16:20] 200 Zzz...

[19:16:50] NOOP

[19:16:50] 200 Zzz...

[19:17:21] NOOP

[19:17:21] 200 Zzz...

[19:17:51] NOOP

[19:17:51] 200 Zzz...

[19:18:22] NOOP

[19:18:22] 200 Zzz...

[19:18:52] NOOP

[19:18:52] 200 Zzz...

[19:19:23] NOOP

[19:19:23] 200 Zzz...

[19:19:53] NOOP

[19:19:53] 200 Zzz...

[19:20:24] NOOP

[19:20:24] 200 Zzz...

[19:20:54] NOOP

[19:20:54] 200 Zzz...

[19:21:25] NOOP

[19:21:25] 200 Zzz...

[19:21:55] NOOP

[19:21:55] 200 Zzz...

[19:22:26] NOOP

[19:22:26] 200 Zzz...

[19:22:56] NOOP

[19:22:56] 200 Zzz...

[19:23:27] NOOP

[19:23:27] 200 Zzz...

[19:23:57] NOOP

[19:23:57] 200 Zzz...

[19:24:28] NOOP

[19:24:28] 200 Zzz...

This is not the transfer log. You can it by double clicking the file in the transfer queue.

There is a problem is that the SmartFTP never receives the 266-File successfully transferred messages and therefore the transfer times out. This could be caused by many things. Some of them:
- Software firewall
- Antivirus product
- Operating system
- Router
- Connection
- Server
- Client

You can try to install a fresh installation of Windows 7 on another computer. This way you can find out if it is related to the first 3 items in the above list.

Unfortunately I lost my second PC to the grim reaper last week, so I have no other one to try. But since I last posted I discovered that my firewall does have a setting I wasn't aware of - sort of hidden away - which is some sort of stealth mode. I disabled that, and things improved quite a bit. However, .png and .jpg files are still very sluggish; they hang for 2-3 minutes, then suddenly will transfer. The next batch of them does the same thing; it is always .png and .jpg files. All other files types now fly off my screen like lightning.

I also did try WS_FTP and FIleZilla. Both clients have the same issue. So I'm not sure what's causing it, especially for only those two image types. In more than ten years of FTP'ing I've seen this sort of thing until now.