Slow Kleopatra performance around 10MB/s


I have problem with encryption and decryption speed using Kleopatra - it takes more than 10 seconds to encrypt or decrypt file of 100MB in size. Thta means performance aound 10MB/s or less ehich is really slow. More info:

  • tested on 2 computers with newest GPG4Win and newest W10 (one i5 16GB RAM and SSD, other i3 8GB RAM SSD) - the same slow performance around 10MB/s
  • encrypting with GPG under Cygwin on those computers is instant so 100MB/s or more
  • tested on Linux machine - performance around 100MB/s with Twofish and 200MB/s with AES256 tested with bigger files
  • my config file disables compression
  • encrypted data are test text file filled with “a” letter to double chck if the file is not compresssed before encrypting
  • tested with symmetric encryption and asymmetric ed25519 and RSA keys, with Twofish and AES
  • creating 4096 bit RSA key does not take long - there is no problem with insufficient random data

What can be the cause? Is it standard performance for Windows version? Why Cygwin performance is much better. Can somebody compare my results?


do you have any network drives involved?

Have you tried to do a decryption natively using the command line? If you install Gpg4win gpg.exe is added to the PATH so you can use it from Windows CMD or Powershell like from Cygwin.

Kleopatra is indeed slower then the command line because data is passed trough multiple layers. We have that somewhat on the radar to improve it for a future version but its kind of rooted in the architecture so its not a simple fix.

Thanks for the feedback,

No, all drives are local SATA attached drives.

Encrypting natively using command line gpg in cmd.exe is much faster as it takes around 3-4 seconds to do encryption. Yet it’s still much slower than Linux version (or Cygwin version on Windows). Cryptographic acceleration when using AES makes those implementations as fast as read/write speed of SSD.

I’m using gpg for backups so I will have to use command line Cygwin version as encrypting few gigabytes of data takes a long time otherwise.