The following will help you troubleshoot common display problems.
My display performance is poor with multiple OpenGL views open
If your OGL views (viewports in shaded display modes, animation mixer, animation editor, and so on) seem sluggish or exhibit poor performance, it is possible that the Vertical Sync (v-sync) option for your graphics card is enabled.
If this option is not disabled, then the maximum refresh rate is the "vertical retrace frequency" divided by the "number of OpenGL views open". For example, if you have a refresh rate of 85Hz and five OGL views are open, the best refresh rate you could get is 17Hz.
On Windows, Softimage tries to enable or disable v-sync according to the Sync Redraw to Display (v-sync) setting in Display Preferences [Preference Reference]. This works only when the v-sync option is set to "Application controlled" or the equivalent in your display driver settings.
If your graphics card and driver does not support application control, or if you are running on Linux, you must disable the v-sync yourself. In the Advanced Display settings for your graphics card, turn off the option to synchronize buffer swap to the Vertical Sync. It should be set to something like "Always off" or "Off by default". You need to restart Softimage.
If you are experiencing problems with other cards that you think may be related to vertical sync, you can set the XSI_NO_VSYNC environment variable. See Environment Variables [Advanced Setup and Configuration].