User Guide


is Slow on X-Servers with SSH Connection

Intel® VTune™
GUI may respond slowly when you run a remote Linux* collection using an X11-forwarding/X-server.


The GUI response may be slow if you use an X-server (for example, Xming*) with SSH on Windows to run the
GUI on a connected Linux machine and the X-server is slow.


Option 1: Enable Traffic Compression
Compression may help if you are forwarding X sessions on a dial-up or slow network. Turn on the compression with
ssh -C
or specify
Compression yes
in your configuration file.
SSH obtains configuration data in the following order:
  • ssh -C
    command-line option
  • user configuration file (
  • system configuration file (
You can explore all available options with
man ssh_config
Option 2: Change Your Encryption Cipher
The default cipher on many systems is triple DES (3DES), which is slower than Blowfish and AES. New versions of OpenSSH default to Blowfish. You can change the cipher to Blowfish with
ssh -c blowfish
Change your configuration file with the
option depending on whether you are connecting with SSH1 or SSH2:
  • for SSH1, use
    Cipher blowfish
  • for SSH2, use
    Ciphers blowfish-cbc,aes128-cbc,3des-cbc,cast128-cbc,arcfour,aes192-cbc,aes256-cbc
You may also follow recommendations provided in the documentation to an X-server you are using.

Product and Performance Information


Performance varies by use, configuration and other factors. Learn more at