UDMA 33/66 compatability?

[teapot]

Can i use udma 33 devices on 66 bus controller?? Or does it work like, udma 33 with 33 controller and udma 66 with 66 controller.
http://www.bevan.kirkman.com

[Bonehead]

You can put a udma 33 device on a /66 controller. But why bother. You won't get 66MB/s (Note: you won't get 66mb/s in real life and the difference between the speed of a 33 controller/device and a '66 contr./device is most of the time not even noticable).

[seti]

Ha, there's about a 1% performance diff. when useing ATA66 over ATA33 on current hard drives. No drive can read info off the platters faster than 33mb's....so the ATA66 only comes into account when reading from the buffer. The only real advantage of ATA66 (currently) is better data integrity.

[AuraEdge]

You can use ATA 33 drives in ATA 66 ports or ATA 66 drives on ATA 33 ports.

Either way, the final speed will be ATA 33

[teapot]

thanks, my question was because i have filled all of my ide ports and saw the new abit board that has 2 33 and 2 66 ports.

[Peter M]

Hi people,

pumping interface bandwidth up into seemingly ridiculous speeds isn't so much about drive performance or throughput.

It's about making PCI bus bandwidth available to other system components. Bringing a subordinate bus (like IDE, SCSI) nearer to the maximum PCI transfer rate of 133 MB/s enables the controller to use the PCI bus more efficiently (i.e. pump larger chunks of data in one go), which will reduce PCI bus time.

In other words, while ATA/66 or U2SCSI doesn't make your harddisk faster, it'll probably make your video frame grabber or AGP game run more smoothly.

This also means, for standard load-compute-store applications, don't bother.

Regards, Peter