Windows in the Enterprise

Terminal Services and CAD

Computer-assisted design (CAD) applications generally don't perform well in Windows Terminal Services environment. Users who try and run CAD apps off of a terminal server will usually experience a slow refresh rate when updating the drawings that makes the user experience frustrating. Clearly Remote Desktop Protocol (RDP) was not really designed for such scenarios.

There are some workarounds you can try if you need to do this however.  You could reduce the screen size from 1280x1024 to 1024x768 if that's workable for you. Reducing the color depth can have even greater impact on speeding up the refresh rate. You should of course have bitmap caching turned on as well.

If you're still in the planning stages of your terminal server environment however, you could also consider implementing Citrix XenApp (formerly Citrix MetaFrame Server and Citrix Presentation Server) as the Citrix terminal server platform includes a technology called SpeedScreen Progressive Display which compresses graphics images for smoother display. If you haven't seen it yet, check out this YouTube video showing RDP and ICA+SpeedScreen in action side by side for comparison—the improvement in screen refresh rate for complex graphics apps is impressive.  You can find more information about SpeedScreen here on the Citrix Web site.

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