ATA/IDE/EIDE TRANSFER MODES

I often used a combination of http://www.pcguide.com/ref/hdd/if/ide/modes.htm and http://www.ata-atapi.com/ as my definitive guides for ATA mode reference. However I got increasingly frustrated with having to flip between different pages to get the whole picture. So I made on big list. All information is pulled from the above two sites which I recommend you read in full because they contain a lot more information that just what's here. However, I hope this will serve as a nice quick reference for anyone who may need it.

Standard Transfer Mode Cycle Time (nsec) Maximum Transfer Rate (MB/s)
ATA PIO 0 600 3.3
ATA PIO 1 383 5.2
ATA PIO 2 240 8.3
ATA DMA Single-word 0 960 2.1
ATA DMA Single-word 1 480 4.2
ATA DMA Single-word 2 240 8.3
ATA DMA Multi-word 0 480 4.2
ATA-2 PIO 3 180 1.1
ATA-2 PIO 4 120 16.7
ATA-2 DMA Multi-word 1 180 13.3
ATA-2 DMA Multi-word 2 120 16.7
ATA-3 Same as ATA-2 - introduced SMART and Security Same as ATA-2 Same as ATA-2
ATA/ATAPI-4 UDMA 0 240 16.7
ATA/ATAPI-4 UDMA 1 160 25.0
ATA/ATAPI-4 UDMA 2 ("UDMA/33") 120 33.3
ATA/ATAPI-5 UDMA 3 90 44.4
ATA/ATAPI-5 UDMA 4 ("UDMA/66") 60 66.7
ATA/ATAPI-6 UDMA 5 ("UDMA/100") 40 100.0
ATA/ATAPI-7 UDMA 6 ("UDMA/133") ?? 133.0 (?)

NOTE: UDMA modes 0, 1, and 2 strongly recommend the use of an 80-conductor cable. To use UDMA modes 3 and up it is required that you use an 80-conductor cable. Note that 40-conductor cables and 80-conductor cables have very similar interfaces, thus a 40-conductor cable will work with a UDMA 3 or higher drive -- but it will drop to UDMA 2. For more information on 80-conductor cables see this page.

A few points on names used. The following are not official names, and in most cases aren't even used correctly - but they are often used in advertising to make things sound cool. Make sure you're not fooled!
And two more points for Windows 2000 users:
Lastly, a similar chart for SCSI can be found at PC Guide here - their main SCSI page is here.


This page is © Phil Dibowitz 2001 - 2004