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


Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice.

Notice revision #20110804