Is this true?

[Maggotry]

I just read on Pinnacle's site (here) that optical drives (DVD, CDRW, etc.) on the same IDE controller as your hard drive will make your hard drive run at the speed of the CD-ROM. I've never heard that before and it just doesn't sound right to me. That means my ATA100 drive is really running at ATA33?? Educate me, please.

 

[Haribo]

<< ...on the same IDE controller as your hard drive will make your hard drive run at the speed of the CD-ROM. >>



oki thats pure BS ofcourse...

and at first I was gone say that all of it was pure BS.. but I'm not sure anymore.

I'm not sure if putting a ATA33 device on a ATA100 cable with another ATA100 device will force the controller into ATA33 mode... I dont think it will but I'm not 100%.

And even if it did that would ofcourse not make your HDD as slow as the CDRom it would only limit the HDDs burst transfer rate. And also limit the speed on newer drives that can have a sustained transfer rate of higher than 33mb/sec.

 

[Haribo]

Oki I looked it up and I think I was right it wont kick it back to ATA33... cause all new ide controlers have something called independent device timing which keep the different devices "separetade" from eachother.

 

[Lord Evermore]

The first ATA33 controllers had the problem, they'd fall back to PIO mode if you put a non-UDMA device on them. That's been fixed for a while.

However you COULD slow down your hard drive by putting an optical device on the same cable. Only one device can be active at a time on a single channel. Think about it, a hard drive that can read at say 30MBps, that has to stop every once in a while to wait for a 32X CDROM reading at 4.8MBps. In the real world, you probably wouldn't see much difference most of the time, but it's possible you'd notice burps in performance for something like a game that reads data both from the hard drive and the CD, or trying to burn a CD on the same channel.

 

[Maggotry]

Where'd you find the info? I didn't find anything about this in the AnandTech FAQ's. My searches have been futile so far. I need a reliable source of info on this.

 

[GT578]

Independent device timing......


I thought that was true ......but connecting my 5400rpm Seagate ATA66 drive as slave to my IBM60GXP .....slows down the IBM.
I checked numerous times with benchmarks and the computer felt slower. I have since put my Promise Ultra100 controller in my computer just for the Seagate and I am using the onboard controller for the IBM.

This is strictly from my experience......but I would never put anything along with my primary HDD unless it was the same model and speed HDD.

 

[Maggotry]

<< The first ATA33 controllers had the problem, they'd fall back to PIO mode if you put a non-UDMA device on them. That's been fixed for a while.

However you COULD slow down your hard drive by putting an optical device on the same cable. Only one device can be active at a time on a single channel. Think about it, a hard drive that can read at say 30MBps, that has to stop every once in a while to wait for a 32X CDROM reading at 4.8MBps. In the real world, you probably wouldn't see much difference most of the time, but it's possible you'd notice burps in performance for something like a game that reads data both from the hard drive and the CD, or trying to burn a CD on the same channel. >>



But an ATA100 HD wouldn't run at ATA33 just because an optical drive was hooked up as slave, right?

 

[Lord Evermore]

Correct. Later ATA33 controllers, and ATA66/100/133 controllers, will run every device at the proper speed.

 

[Maggotry]

Thanks for the help. I was pretty sure the Pinnacle info was wrong, but I just wanted to be sure.