SFTP slower than FTP on Core Server

[qurm]

I have recently installed Core Server and Pro client to replace the standard Windows IIS FTP, to have a more secure service.

Using the default setup, we see that a large file transfer (~1.5GB) is many times slower than previously (was 90 mins, now 8-9 hours). Does the encryption really add this much overhead?

Are there some tuning or settings that can be adjusted to optimise for performance over security?

Would mulitple smaller files transfer more quickly than a single small file ?

Running a short test to transfer of the same file (running for a few minutes, then stopping) I see these ratse in the Queue window.
FTP 61Kbs
SFTP 53Kbs
This seems a more reasonable difference in rates.

Thanks for any advice

[tschuld]

I see this was posted 4 months ago but some answer should be better than no answer...

The short answer is yes - SFTP puts a major load on the CPU components and has a significant throughput difference. The smaller the available CPU resources the more significant the difference. Both ends are effected, the sender and receiver cpu resources factor in with the smallest CPU resource being the bottleneck. So it doesn't matter if your server side has say a 4 socket, quad core Xeon monster board if your sending unit is for example a utility box with a single core 1.8 - It's the 1.8 that controls the show under sftp.

No matter what horsepower you throw at sftp, it will never match the raw speed of ftp.