ATA-100 vs ATA-66 vs ATA-33

[devlin]

If you have a MoBd that supports ATA100 and you slave an ATA-66 or ATA-33 HD or CDR in the system, how badly will it degrade the system performance overall? Is there anyplace that I can get more info on the difference?

Devlin

[Underseer]

Don't quote me on this, but I'm sure the ATA-100 device will "downshift" to the lowest common denominator on that same channel.

The good news is that modern hard drive mechanisms simply can't fill an ATA-100 pipe, so you're unlikely to notice the shift from ATA-100 to ATA-66.

[Wayward Clam]

Whot Underseer says is whot I've heard too, but I can't confirm it as 100% positive.

[http://forums.windrivers.com/cgi-bin/forum1/noncgi]

Mixing PIO drives with DMA or UDMA drives will force them both to run in PIO mode. In other words, if you combine a UDMA-100 drive with a PIO mode 4 drive, both will operate at PIO mode 4.


However, since modern motherboards support independent timing, you can mix and match DMA and UDMA devices running at different speeds without any performance loss. In otherwords, if you slave a UDMA-33 drive to a UDMA-100 drive, the 100 will still run at 100 and the 33 will still run at 33.

It is important to note that older ATAPI Zip drives used PIO mode 0. Attaching it on the same controller as anything else will cause a HUGE performance hit!

[Commander Klarg]

So, if I'm using a UDMA 33 capable drive (master) on the primary controller with a Mode 4 drive (slave), I'm still running in Mode 4 on the faster drive?

My secondary controller is running a UDMA 33 capable CD-RW as master. Should I swap the Mode 4 HD with the CD-RW so that both UDMA 33 devices are on the same controller? Or should the CD-RW and Mode 4 HD share the secondary controller?

Either way, it will require re-deranging ( ) the guts of the system. Oh well....