File upload speed is 3 times slower after updating to 4.3.7

My file upload speed is 3 times slower after updating to version 4.3.7

Yesterday I updated WinSCP to version 4.3.7 (build 1679) and now my file upload speed is 3 times slower than it was before the update. I have confirmed the problem is from WinSCP by comparing the upload time when using cPanel's file upload feature and WinSCP always takes 3 times longer to upload the same file. Before updating to version 4.3.7 WinSCP was always faster than when using cPanel's file upload feature.

I have also checked my Internet connect upload speed at speedtest.net and speakeasy.net/speedtest/ and it is consistently averaging 3.8 Mbps

Any help would be appreciated.

What version of WinSCP were you using before the upgrade?

martin wrote:

What version of WinSCP were you using before the upgrade?

I kept the software current so I am assuming it was version 4.3.6

I also uninstalled WinSCP and did a clean install and I still have the same problem.

I have also done several tests comparing the upload and download speeds of WinSCP with FileZilla using the exact same conditions for both programs and my test results show that FileZilla is 4 to 5 times faster.

Before version 4.3.7 WinSCP was always faster than FileZilla.

Can you please downgrade to 4.3.6 to verify?
Also, what protocol are you using?

I do have the exact same problem. The problem started with version 4.3.7.
I downgraded (replaced the .exe file) to version 4.3.6 and the problem persists :cry:

By the way protocol is SFTP.

Anonymous wrote:

I do have the exact same problem. The problem started with version 4.3.7.
I downgraded (replaced the .exe file) to version 4.3.6 and the problem persists :cry:

Are you sure you were using 4.3.6 before you upgraded?

To 99%, yes I am.

I just tested winscp 4.3.6. on a laptop I played around with winscp 5.0.7. beta before.
I get an upload speed of ca. 370 kbps. :cry:
On the same laptop I get 680 kbps with webdrive. Both webdrive and winscp use the SFTP protocol.
Are there some new reg-entries since 4.3.7.?

Ok, I'm back on my workstation (same network), found a winscp version 4.3.2 in an old backup. Downgraded to this one (installed over the 4.3.6 version).
Now I get an upload speed of 580 kbps, much better. :D
With webdrive I get something around 640 kbps.

So, maybe it was after version 4.3.2 the upload speed went down? :roll:

That would make sense. In 4.3 optimization to SSL channel buffer size was introduced. It was rolled back in 4.3.3 as some users were having problem with it. It was reintroduced in 5.0.3 beta with option to disable.

https://winscp.net/tracker/615

Ok, thank you. I'm sticking to 4.3.2. for now. Can't wait for the 5.0.x non beta, I'd like to automate some things. :D