Abit IT5A User Manual page 70

E-2
The higher the MODE value is, the better the hard disk data transfer rate.
But this does not mean that you can select the highest mode value as you like.
You must be sure that your hard disk supports that type of fast data transfer,
otherwise your hard disk will not be able to operate correctly.
Here are some examples of data transfer rates for IDE HDD with DMA
mode:
DMA Mode 0 The fastest data transfer rate reaches 4.16Mbyte/sec
DMA Mode 1 The fastest data transfer rate reaches 13.3Mbyte/sec
DMA Mode 2 The fastest data transfer rate reaches 16.6Mbyte/sec
Usually, PIO mode means the hard disk data is only accessed by the CPU
through the chipset and placed into memory, and the chipset is using PIO mode
to access hard disk data.
MASTER mode means that hard disk data is accessed by the chipset, and
the chipset places the data into memory. The chipset uses DMA or PIO mode to
access data stored in the hard disk drive. The Master mode can reduce the CPU
load, especially in a Multi-task environment. This can help system performance.
Appendix E