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The FileZilla uses a PuTTY/psftp source code for an SFTP implementation. Actually the FileZilla runs a hidden PSFTP sub-process.

But it uses its own build of PSFTP (FzSFtp.exe) that employs few optimizations (and other modifications), including:

• SFTP transfer queue is 4 MB (comparing to 1 MB in PSFTP)
• Allocates memory in much larger chunks (32 KB comparing to 515 B)
• Uses large network buffers (4 MB for SO_RCVBUF and 256 KB for SO_SNDBUF). PSFTP keeps the system defaults.

FileZilla also uses a different compiler (mingw) than PuTTY (VS), what may contribute.

WinSCP is also based on PSFTP code (though it uses PSFTP code internally, not in an external sub-process) and uses a similar set of optimizations.

The FileZilla uses a PuTTY/psftp source code for an SFTP implementation. Actually the FileZilla runs a hidden PSFTP sub-process.

But it uses its own build of PSFTP (FzSFtp.exe) that employs few optimizations (and other modifications), including:

• SFTP transfer queue is 4 MB (comparing to 1 MB in PSFTP)
• Allocates memory in much larger chunks (32 KB comparing to 515 B)
• Uses large network buffers (4 MB for SO_RCVBUF and dynamic size for SO_SNDBUF [using SIO_IDEAL_SEND_BACKLOG_QUERY]). PSFTP keeps the system defaults.

FileZilla also uses a different compiler (mingw) than PuTTY (VS), what may contribute.

WinSCP is also based on PSFTP code (though it uses PSFTP code internally, not in an external sub-process) and uses a similar set of optimizations.

The FileZilla uses a PuTTY/psftp source code for an SFTP implementation. Actually the FileZilla runs a hidden PSFTP sub-process.

But it uses its own build of PSFTP (FzSFtp.exe) that employs few optimizations (and other modifications), including:

• SFTP transfer queue is 4 MB (comparing to 1 MB in PSFTP)
• Allocates memory in much larger chunks (32 KB comparing to 515 B)
• Uses large network buffers (4 MB for SO_RCVBUF and 256 KB for SO_SNDBUF). PSFTP keeps the system defaults.

WinSCP is also based on PSFTP code (though it uses PSFTP code internally, not in an external sub-process) and uses a similar set of optimizations.

The FileZilla uses a PuTTY/psftp source code for an SFTP implementation. Actually the FileZilla runs a hidden PSFTP sub-process.

But it uses its own build of PSFTP (FzSFtp.exe) that employs few optimizations (and other modifications), including:

• SFTP transfer queue is 4 MB (comparing to 1 MB in PSFTP)
• Allocates memory in much larger chunks (32 KB comparing to 515 B)
• Uses large network buffers (4 MB for SO_RCVBUF and 256 KB for SO_SNDBUF). PSFTP keeps the system defaults.

FileZilla also uses a different compiler (mingw) than PuTTY (VS), what may contribute.

WinSCP is also based on PSFTP code (though it uses PSFTP code internally, not in an external sub-process) and uses a similar set of optimizations.

The FileZilla uses a PuTTY/psftp source code for an SFTP implementation. Actually the FileZilla runs a hidden PSFTP sub-process.

But it uses its own build of PSFTP that employs few optimizations (and other modifications), including:

• SFTP transfer queue is 4 MB (comparing to 1 MB in PSFTP)
• Allocates memory in much larger chunks (32 KB comparing to 515 B)
• Uses large network buffers (4 MB for SO_RCVBUF and 256 KB for SO_SNDBUF). PSFTP keeps the system defaults.

WinSCP is also based on PSFTP code (though it uses PSFTP code internally, not in an external sub-process) and uses a similar set of optimizations.

The FileZilla uses a PuTTY/psftp source code for an SFTP implementation. Actually the FileZilla runs a hidden PSFTP sub-process.

But it uses its own build of PSFTP (FzSFtp.exe) that employs few optimizations (and other modifications), including:

• SFTP transfer queue is 4 MB (comparing to 1 MB in PSFTP)
• Allocates memory in much larger chunks (32 KB comparing to 515 B)
• Uses large network buffers (4 MB for SO_RCVBUF and 256 KB for SO_SNDBUF). PSFTP keeps the system defaults.

WinSCP is also based on PSFTP code (though it uses PSFTP code internally, not in an external sub-process) and uses a similar set of optimizations.