CPU-Bound Applications and Windows NT

Because the Windows NT screen savers run at a lower priority than applications with Windows NT, it is possible for a CPU-bound application to make the system inoperable.

A CPU-bound application is an application that constantly interrupts the processor in case there is data to be processed. An example of a CPU-bound application is the Slide Show in Microsoft PowerPoint.

If the Windows NT screen saver activates while the CPU-bound application is in the foreground, the screen saver thread will essentially become starved for CPU cycles because other applications run at a higher priority. Depending on how the CPU-bound application is written, keystrokes and/or mouse movements may not be passed on to the functioning Windows NT screen saver application. If they are not, the computer is essentially locked up.

By default, the screen saver runs at a base priority of 4 and applications run at a base priority of 7.

The only current workaround for this is to disable the screen saver.