Hack #71. Choose the Correct AGP Mode

Tell your system BIOS to throttle up the AGP bus for the best video data throughput.

Most recent video cards support AGP 4x and 8x, but not all system boards do. AGP 1x and 2x run off 3.3 volts, while AGP 4x and 8x use 1.5v power. AGP 4x and 8x cards are keyed so they will not plug into a 1x- or 2x-only slot.

Maximum performance is obtained by using the highest AGP clocking value your system and video card will support. In other words, if you have an AGP 8X card and you have a BIOS parameter that sets the AGP mode (2X, 4X, 8X) that is set to 4X, your AGP card will not be running at its best performance. This parameter may be automatically set by your BIOS (you see only a display of the automatically determined parameter), or you may be able to override the setting to a lower or higher value than appropriate. If your system BIOS defaults to a 1X setting but you have a 2X video card, by all means set the value to 2X. If your system BIOS defaults to a 4X setting but you have an 8X video card, set the value to 8X.

The AGP Mode setting can be found in your BIOS settings (see Table 1-1 in [Hack #3] ), usually under Advanced Settings or Advanced Chipset Features.

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