Setting Graphics Compatibility Options

In Windows 98, graphics hardware acceleration features can be turned off when system performance indicates incompatibility problems. Specifically, problems can occur when Windows 98 assumes a display adapter can support certain functionality that it cannot. In such cases, the side effects might be anything from small irregularities on the screen to system failure. You can disable hardware acceleration features of the display adapter so that the computer can still be used if there is a problem with the display adapter. If changing these settings fixes otherwise unexplained system crashes or performance problems, the source of the problem is probably the computer’s display adapter.

To change graphics performance settings

1. In Control Panel, double-click System, click the Performance tab, and then click Graphics.
2. Drag the slider to change the Hardware acceleration setting, as summarized in the following list. Then click OK.
   • The default setting is Full, which turns on all graphics hardware acceleration features available in the display driver.
   • The first notch from the right can be set to correct mouse pointer display problems. This setting disables hardware cursor support in the display driver by adding SwCursor=1 to the [Display] section of System.ini.
   • The second notch from the right can be set to correct certain display errors. This setting prevents some bit block transfers from being performed on the display card and disables memory-mapped I/O for some display drivers. This setting adds SwCursor=1 and Mmio=0 to the [Display] section of System.ini, and SafeMode=1 to the [Windows] section of Win.ini.
   • The last notch from the right (None) can be set to correct problems if your computer frequently stops responding to input, or has other severe problems. This setting adds SafeMode=2 to the [Windows] section of Win.ini, which removes all driver acceleration support and causes Windows 98 to use only the device-independent bitmap (DIB) engine rather than bit block transfers for displaying images.

     For example, an error message at system startup stating that an application caused "an invalid page fault in module <unknown>" would indicate a problem between the display driver and the Windows 98 DIB engine. In such cases, this setting should correct the problem.

For more information about the built-in graphics performance features in Windows 98, see Chapter 24, "Device Management," and Chapter 28, "Windows 98 Architecture."