FTP sync slow with TLS

[tsukraw]

I have this setup with a FileZilla ftp server. It all works good sync/upload/download when in normal mode but when i turn on TLS encryption it is very very slow. The upload and download run just fine. It is just the sync that is comparing of the files that is slow.
I have tired this local to the server and same results as if on the WAN. I know specs make a difference in speed of the encryption/decryption but the server and client computer i am testing with show be very well up to speed for this.

Is there anything that is know for this issue or what can be done?
Other FTP clients i do not see this issue so i am lead to believe this is a SuperFlexible issue.

[somusque]

Never heard of this but you can try various settings:

FTP Library 1,2,3
FTP Listing command

These are all on the FTP dialog.