Hard drive not running in fastest supported mode

tipoo

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May 4, 2006
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Hey guys...I was just doing some maintenance on my old family desktop (for the first time since getting my new laptop, lol) when i realized that the drive is not running at its full supported speed. HD Tune reports that its max supported speed is ATA100, but its running at ATA33! That would explain why the results are always close to a straight line for its benchmark, the drive is limited at 33mb/s!

So does anyone know how to set it to its maximum supported speed? I've looked in the BIOS and don't see anything there, where else could it be?
 
Solution
To get ATA100 performance, you need three things: both the disk itself and its controller need to work that way, PLUS you must have the proper ribbon cable. The original ATA ribbon cables had 40 wires in them with 40-pin connectors. But a later better design uses 80-wire cables, still with the same 40-pin connectors on the ends. In that design, every second wire is a ground lead and it prevents signals from mixing between the lines. Cleaner signals allow the system to run faster. So, look closely at the ribbon cable and start counting over from one edge. If you get to 10 wires and you're already 1/4 across the ribbon, you have the older style, so replace it.

Other than that, BIOS settings can play a role. But they don't often say...

donpacific2k

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Dec 23, 2008
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Here's a silly question; are you using the ribbon cable with the blue lines/end? (something rated at ata-100 or above) That was the first thing I thought when dealing with ancient computers... the old ribbon cables only have 40 (or is it 39?) wires, not enough to get past the ata-33 speeds.
 

Paperdoc

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To get ATA100 performance, you need three things: both the disk itself and its controller need to work that way, PLUS you must have the proper ribbon cable. The original ATA ribbon cables had 40 wires in them with 40-pin connectors. But a later better design uses 80-wire cables, still with the same 40-pin connectors on the ends. In that design, every second wire is a ground lead and it prevents signals from mixing between the lines. Cleaner signals allow the system to run faster. So, look closely at the ribbon cable and start counting over from one edge. If you get to 10 wires and you're already 1/4 across the ribbon, you have the older style, so replace it.

Other than that, BIOS settings can play a role. But they don't often say ATA100; instead they will talk about PIO modes, etc. The higher the better, but your system will limit you on how high you can set it. Part of the limit is imposed by the measured capabilities of your system, so make sure you're using an 80-conductor cable before trying to change this.

Another small point. ATA ribbon cable standards limit the cable length to 18" tops, so if you are using a cable longer than this it MAY limit your speed. I've been getting away with 24" cables for a while, but that does not always work.
 
Solution

tipoo

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May 4, 2006
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Never mind fellas...I found my problem. The last time i was tinkering with something inside, i swapped the connector cables for the hard drive and the CD drive, not realizing one was an 80 pin and one was a 40 pin. Swapping them and restarting fixed the problem, its much faster now. I'm surprised i didnt notice this difference before. Silly me.


Thanks for the replies nonetheless.
 

Paperdoc

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By the way, using a 40-conductor cable for the optical drive is a trick I used for many years, but it depends on the idea that optical drives (especially old ones) cannot do ATA66 or ATA100 anyway, so why bother with high-seed cables? BUT modern opticals CAN run at the faster speeds, especially DVD drives. So you MAY find a small advantage to switching that cable to 80-conductor also. Just depends on what optical drive you have.