40 vs 80 conductor IDE cable interchangeability...

Asparagus

Senior member
Aug 16, 2001
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I only have the right lengths of cables in the if I do the following...

IDE 1 = 80 conductor HDD master, Optical drive slave
IDE 2 = 40 conductor 2nd HDD slave, 2nd Optical drive slave

Any issues with using 40 conductor to one channel and 80 to another?

Begs the question what 80 conductor does for me vs 40???? I assume since they both have 4 o receptacles to fit in 40 pins on the drives that one can use a 40 OR an 80 pin on a given drive with no issues right???
 

MedicBob

Diamond Member
Nov 29, 2001
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The difference is in speed/standards. 80 way/pin cables are for ATA 66 and higher speeds, ie HDD. 40 way/pin cables and for ATA 33, ie DVD/CD. You can run HDD on the 40, but speeds will take a hit.

Why not put both HDD on the 80 and both Opticals on the 40? I know you are concerned on length, but I don't see why it wouldn't work.
 

sonoma1993

Diamond Member
May 31, 2004
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Originally posted by: Asparagus
I only have the right lengths of cables in the if I do the following...

IDE 1 = 80 conductor HDD master, Optical drive slave
IDE 2 = 40 conductor 2nd HDD slave, 2nd Optical drive slave

Any issues with using 40 conductor to one channel and 80 to another?

Begs the question what 80 conductor does for me vs 40???? I assume since they both have 4 o receptacles to fit in 40 pins on the drives that one can use a 40 OR an 80 pin on a given drive with no issues right???

why not just put both hdd on the 80 conductor cable and put both optical drives on the 40 conductor cable?
 

Aluvus

Platinum Member
Apr 27, 2006
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Originally posted by: Blain
Odd that the connectors for both are 40 pins.

It provides backwards compatibility. Otherwise, older equipment would need its own cable (which would become harder and harder to buy over time) separate from newer equipment.

@OP: The 80-wire cable has extra wires to reduce crosstalk (they are all connected to ground). This permits operating at higher speeds without unacceptably high error rates. 40-wire cables are, as stated, fine for optical drives and will work for hard drives provided you're willing to give up performance.

Given that new IDE ribbons cost about $5, I'd just buy a new cable. Or rearrange the drives.
 

Paperdoc

Platinum Member
Aug 17, 2006
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As others have said, the 80-conductor cables simply put a ground line between every other line to reduce cross-talk or signal leak betweeen adjacent lines. This allows higher data rates. But all optical drives operate at the lower data rates (ATA33 or less) so they don't need this.

One solution is to rearrange and put 2 HDD's on the faster 80-conductor cable and 2 Opticals on the slower one. Compared to this, one advantage of your current arrangement (hypothetically) is that is gives each HDD its own IDE port which MIGHT speed up simultaneous access to the two. But since the cable is slowing down one of them, anyway, that advantage may have been lost. Similarly, the Opticals are on separate IDE ports so MAYBE a copy operation between the two might be better the current way.

Best advice already given: buy another 80-conductor cable and keep your current arrangement. Hypothetically that is optimum.
 

bendixG15

Diamond Member
Mar 9, 2001
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Only the old optical drives use the 40 wire cable

The recent optical drives operate at Ultra DMA speeds and need the 80 wire cable.

My Pioneer DVR-111D, about 6 months old, operates at ULTRA DMA Mode 4

Throw out those 40 wire things and get the 80 wire jobs.
 

corkyg

Elite Member | Peripherals
Super Moderator
Mar 4, 2000
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BendixG15 is right. Ribbon cables are too cheap to mess with. Trash the 40-wire cables and replace them.

As for the connectors - they are exactly the same for both - 40 pins. The difference is between the pins - 2 wires per pin instead of one.

If your optical drives are old, then you can put both on the 40 wire cable and both HDDs on the 80 wire one.