[Solved] SFTP - Download Speed limited at ~5.5 MB/Mo (Tested and work)

[Canan]

Hi,

I have a download speed limitation when I try to download a list of files from my server with FreeFileSync.

My setup is :
- FreeFileSync (up-to-date)
- Windows 10 x64 (up-to-date)
- AMD Ryzen 3700X
- my internet connection is 300Mb (~37.5 MB/Mo) in RJ45
- the server has 100Mb (~12.5 MB/Mo) internet connection
- the bandwidth of the server is not limited
- there is no download or upload on the server at the same time
- my HDD local is a 7200RPM in SATA3, so ~350 MB/Mo write speed
- I use an SFTP connection in FFS to connect to the server

When I download the same file from :
- direct link (HTTP) = ~11.5MB/Mo
- Filezilla (SFTP) = ~11.5MB/Mo
- FreeFileSync (SFTP) = ~5.5MB/Mo
-> So the problem is CLEARLY from FFS. ^^

I think I found a lot of person with a similar problem:
- viewtopic.php?t=6513&p=21420
- viewtopic.php?t=6643&p=22037
- many others, etc.
But I never found a clear solution or simply don't work for me.

Already have a look at the FAQ and find nothing.
Link: https://freefilesync.org/manual.php?topic=ftp-setup

For now, I can't have more than ~5.5 MB/Mo download speed when I should have ~12.5 MB/Mo download speed (because of the lower part of my connection is the server internet connection).
Perhaps an FFS setting or something to do for the next update?

Can someone help me?

EDIT: Corrected in the new version, I quote the Dev/Admin: "I've done a few tests and it turns out FFS does indeed have an SFTP perf issue with single connections! Luckily it's one that is easily fixed by increasing the buffer sizes."

Thank you in advance,
Best regards.

[xCSxXenon]

What are your transfer speeds when copying normally? You will never see theoretical maximum speeds in the real world. Your 100mb connection is severely limiting in the first place. 70%-80% of theoretical speeds is common, so that would be 8.75-10mb for the network connection alone. Factor in overhead on the hard drive, and 5,.5 isn't out of the realm of possibility. An SSD would be preferable, but a HDD for storage and separate from the OS can help significantly.

[Canan]

Hi,

@xCSxXenon Thank you for answer.

When I downlaod the same file from :
- direct link (http) = ~11.5MB/Mo
- Filezilla (sftp) = ~11.5MB/Mo
- FreeFileSync (sftp) = ~5.5MB/Mo
-> So the problem is clearly from FFS ^^

Perhaps a setting or the Donator version is required?

Does nobody have this problem or an explication?
Perhaps, only the creator and Admin can answer me?

Thank you in advance,
Best regards.

[xCSxXenon]

There is no speed limiter in any version of the program. I wonder if it is accessing under a different account and causing extra computation for ACLs/permissions. Can you try changing the "parallel threads" setting and trying again?

[Canan]

Hi,

@xCSxXenon Thank you for the answer.

There is no movement on it (no UP, no DL) at the same time.
As I said I have ~11.5MB/Mo if I DL with "direct link" or "Filezilla".
I am the only user and use the same identifiers for all tests and connections and in the same conditions.

I can't edit "parallel threads" because I have a free version (I already ask twice if it can help or not have a donator version for this problem).
"Left" and "Right" threads are set to 10 by default

-> Perhaps, only the Dev/Admin can answer me?

Thank you in advance,
Best regards.

[xCSxXenon]

Try excluding the FFS executable in Windows defender or your other AV

[Canan]

Hi,

@xCSxXenon Thank you for the answer.

I never added "Filezilla" in AV exclusion and I can't no anything for "direct link", but they work both normally. ^^

I added FFS in my AV exclusion, but there are no changes.

Thank you in advance,
Best regards.

[Canan]

Hi,

Perhaps, only the Dev/Admin can answer me?
And can say me if "parallel threads" will help or not. ^^

Thank you in advance,
Best regards.

[Canan]

Hi,

@Zenju Please, can you help me?

Thank you in advance,
Best regards.

[Zenju]

And can say me if "parallel threads" will help or not. ^^

Yes parallel threads will probably help. Looks like your server is limiting the download rate at 5Mb/sec per connection.

[Canan]

Hi,

Thank you for your reply.

As I said, when I download the same file from :
- direct link (HTTP) = ~11.5MB/Mo
- Filezilla (SFTP) = ~11.5MB/Mo
- FreeFileSync (SFTP) = ~5.5MB/Mo
-> So the problem is CLEARLY from FFS. ^^

So have you an idea?

Best regards.

[Zenju]

Please read my last response (more carefully).

[Canan]

Hi back,

Thank again for help. ☺

When I make a download from Filezilla (SMTP) on a big file I got ~11.5MB/Mo, so with a single connection.
When I do the same download test with FFS, I got 5.5MB/Mo, so again a single connection also, so half of download speed from Filezilla test in same condition.
How it is possible?

Best regards.

[Zenju]

I got ~11.5MB/Mo, so with a single connection.

I've done a few tests and it turns out FFS does indeed have an SFTP perf issue with single connections! Luckily it's one that is easily fixed by increasing the buffer sizes.

Here's the new version for testing:
https://www.mediafire.com/file/k2c3oz5ann9t4qr/FreeFileSync_10.24_%5BBeta%5D_Windows_Setup.exe

[Canan]

Hi back,

It works perfectly now. ☺
So I have full available speed (50% more than before, in my case).

In all cases, I am glad I insisted on your forum because I was able to help you detect and correct a problem, which will undoubtedly be very useful for everyone.

Best regards.


Edit: After different tests, I don't know if it is because it is a beta version (so not the final new release), but the new speed for a single connection is not totally stable (start at 10MB/Mo few minutes, then go down to 7MB/Mo until the end).

[Zenju]

In all cases, I am glad I insisted on your forum because I was able to help you detect and correct a problem, which will undoubtedly be very useful for everyone.

Good work ;)

Edit: After different tests, I don't know if it is because it is a beta version (so not the final new release), but the new speed for a single connection is not totally stable (start at 10MB/Mo few minutes, then go down to 7MB/Mo until the end).

Measurement error, hopefully...

[Canan]

Hi,

After many other tests, you have right, it was just a measurement error. ^^
So your new feature/correction works well, I edited my title and first message.

I guess everybody will have this correction in the next official release?

Good job and thank you again. =)