TC FTP with poor upload speed on one PC

[sidefx88]

Hi, I have an Internet connection at home with 700 Mbps downstream and 700 Mbps upstream aprox.

On my main computer, TC uploads files to a FTP with very limited bandwidth (100 Kb/s).
But on another computer TC uploads files to a FTP at high speed (15 Mb/s).

I've tested this again and again and I can't find the cause.

-Same files used to do upload tests on both computers.
-Same TC version (11.0) on both computers.
-Same FTP server and FTP mode on both cases (passive mode disabled, but I've also tried PASV mode ON, same results).
-No SSL/TSL used on this FTP Server. It is a plain, classic FTP server.
-No transfer limit set on both cases.
-Both computers are connected using a Cat.6 Ethernet cable.
-Both computers use Windows 11 22H2.
-No firewall, VPN, proxy, or antivirus are being used or active during these upload tests on both PCs.
-I've also tried default TC settings to avoid some unknown "limit" feature.

Here are some screenshots of both computers and they real down/up bandwidth:

TC on the computer with no upload problems:
Image: https://periodictableofsynthpop.com/tc_ftp/FAST_Asus.jpg

TC on the computer with the problem:
Image: https://periodictableofsynthpop.com/tc_ftp/FAST_Core_i7.jpg

FAST on the computer with no upload problems:
Image: https://periodictableofsynthpop.com/tc_ftp/Asus_upload.jpg

FAST on the computer with the problem:
Image: https://periodictableofsynthpop.com/tc_ftp/Core_i7_upload.jpg

Any suggestion?
I'm really out of clues about what can be causing this strange behaviour.
Maybe a hidden setting on TC?

Thanks in advance!

[Dalai]

You should compare the wcx_ftp.ini files of both systems, primarily the [General] section. Look for a setting named UploadBlockSize. If it's there, it's most likely responsible for an increased speed.

Regards
Dalai

[sidefx88]

Thanks for your reply, dalai!

Here is the [General] section of wcx_ftp.ini, it is the same wcx_ftp.ini fil on both computers (the "fast" one and the "slow" one).
I've also included other sections as [default] and [firewall]:

[default]
pasvmode=0
ViaLocalPC=1
[General]
e-mail=asd@asd.com
ConnectRetries=10
WaitDelay=5
transfermode=I
LogFile=
FtpInBackground=0
ModeZ=1
AutoResume=30
FtpOpenIn=1
[firewall]
Method=5
host=192.0.0.1

And here's the FTP server section:

[xxxxxxxx]
host=ftp.xxxxxxxxxx.com
username=xxxxxxx
password=xxxxxxxxxxxxxx
pasvmode=0
directory=/xxxxxxx/
localdir=E:\xxxxxxxxx

Same .ini file, same settings, but the problem persists. On one PC the FTP transfers go really fast, and on my main PC it goes really slow.

By the way, this week I've upgraded my main PC, the one that goes really slow on FTP transfers.
So, it has a new CPU (i7 14700KF), new RAM modules (64 GB DDR5), new motherboard, so new integrated LAN interface (now 2.5 Gbps, another MAC address, etc.), but in the upgraded computer the problem persists!

No "UploadBlockSize" setting on any of the two PCs. Do you have some additional info about it and how to use it in order to increase transfer speeds?

Thanks again!

[Dalai]

Well, if the setting is not in there, the vastly different speeds are probably due to a difference in the networking stack, e.g. driver versions, driver settings, the NIC itself and similar factors. I suggest to add the UploadBlockSize with a reasonable value - see TC help, section 4.b for an explanation of this setting and its possible values. IIRC I've seen values of 16384 or 32768 here in the forum.

Regards
Dalai

[sidefx88]

I've tried those settings (UploadBlockSize=8192 and UploadBlockSize=16384, even UploadBlockSize=32768), but nothing seems to work.

I've connected the slow-FTP-PC via WiFi and disconnected the LAN cable: same results.

I've installed a clean TC 11.02 x86 and even x64, but same results...

I really don't know what can be causing this poor speed transfer.

[Dalai]

Did you add UploadBlockSize to the correct section of wcx_ftp.ini? Did you restart TC after making these changes?

A firewall, anti-virus, internet security, malware scanner or similar program could be responsible for the slower speeds.

Regards
Dalai

[sidefx88]

Yes, I put UploadBlockSize setting inside the [General] section of wcx_ftp.ini.
Besides, I've closed and reopen TC.

As I mention before, no firewall, VPN, proxy, or antivirus are being used or active during these uploads.

I just tried uploading different kind of files, from different drives (C:, D:, F:, all of them are high speed SSD or NVMe): the problem persists.

I've set different DNS, and also I've reset TCP/IP config, adapter, ARP cache, DNS cache..., but same results: FTP uploads up to 350 Kbps.

Using my other computer, same network, same FTP client and version: TC 11.01, same uploaded files, same FTP server, the uploads go up to 15 Mbps!!! (43 times faster!)

I'm running out of clues

Thanks anyway, Dalai!

[Dalai]

What is the (net) bandwidth of the WiFi connection? Wireless connections are usually much slower than wired ones, and the advertised speeds of WiFi cards/chips are much higher than what can be achieved in reality.

Can you check the upload speed with a different program like FileZilla?

Regards
Dalai

[sidefx88]

Using WiFi I got 450 Mbps downstream and 350 Mbps upstream testing it with www.fast.com

Using other FTP clients like Filezilla I got 15 Mbps, so the problem seems to be TC on this specific PC

[Dalai]

Well, I don't know anything other than UploadBlockSize. Maybe increase its value further, e.g. by a factor of 10 or 100 or so.

Regards
Dalai

[petermad]

2sidefx88

What happens if you go back to TC 11.01 on the slow PC (like you have on the fast PC) ?

[sidefx88]

2petermad:

I've tested it in both computers, using the same TC folder: same version, same settings, same config files, but the problem persists.

2dalai:

I've tried using different UploadBlockSize values: small, medium and big. Same results on all cases

[bsh]

I'm having the same(?) issue and I too narrowed it down to TC.

[ghisler(Author)]

If your server supports SFTP, you can try the newest beta of the plugin: It now supports variable block sizes for uploads and downloads.
viewtopic.php?p=449153#p449153

It's used via Alt+F1 - Drive "\" - "Secure FTP".