The Ultra DMA (UDMA) interface was the fastest method used to transfer data between the computer (through the ATA controller) and an ATA device until Serial ATA. UDMA took over from Single/Multiword DMA as the choice of interface between ATA devices and the computer. The UDMA interface is grouped into different modes ranging from 0 to 6 each with its own specifications.
| Mode | Number | Also called | Maximum transfer rate (MB/s) |
Defining standard |
|---|---|---|---|---|
| Ultra DMA | 0 | 16.7 | ATA-4 | |
| 1 | 25.0 | ATA-4 | ||
| 2 | Ultra ATA/33 | 33.3 | ATA-4 | |
| 3 | 44.4 | ATA-5 | ||
| 4 | Ultra ATA/66 | 66.7 | ATA-5 | |
| 5 | Ultra ATA/100 | 100 | ATA-6 | |
| 6 | Ultra ATA/133 | 133 | ATA-7 | |
| 7 | Ultra ATA/167 | 167 | CompactFlash 6.0 |