Will installing an Ultra ATA cable backwards affect performance?

1

I've recently purchased a hard drive upgrade for my Xbox: 320GB WD Caviar Blue WD3200AAJB and StarTech.com Ultra ATA/66/100/133 cable IDE66 (yes I'm crazy).

When it came to installing the cable, it was too short (my fault), and there wasn't enough space between the master and slave ends to reach both the DVD drive and the hard drive. The only thing I could do was install the cable backwards and twisting it quite a bit to make it fit.

The upgrade works, but reading the manual for the hard drive I replaced (10GB Seagate U Series 5), apparently there is a specific way you have to connect the cable.

I don't have that option, so the question comes down to, will my drive performance be at Ultra ATA levels, or is it still performing at original ATA speeds?

Is there any way I can test this (benchmarking software for Xbox)?

cyanic

Posted 2012-06-27T20:46:09.290

Reputation: 189

1You mean the grey/blue/black connectors on the cable? The obvious/intuitive answer would be no, wires is wires, but the problem is that with an 80-conductor ribbon, they don't all connect to all the pins. I don't have specs on hand, so don't take this as gospel, but it may indeed reduce the speed if both the motherboard IDE controller and the drive are ATA100+. Usually it should not cause a problem in your scenario though because the only other device on the cable is a DVD drive. If it were another ATA100+ drive, then yes, you would need to make sure they all line up and connect correctly. – Synetech – 2012-06-27T21:24:06.667

Answers

3

On a normal PC using a wrong connector for the host will prevent detection of a 80 conductor cable due to the missing short between pin 34 and ground and thus reduce maximum transfer mode to Ultra DMA 2 (33 MB/s). Unfortunately I don't know if a Xbox behaves the same and if there is some benchmarking software. I suggest to simply do some I/O operation and check if speeds get above 33 MB/s.

Gurken Papst

Posted 2012-06-27T20:46:09.290

Reputation: 3 874

I'm seeing a peak of 13685 KB/s when copying a test 512MiB file filled with random bytes from one partition to another. Looks like original ATA speeds to me. I read that the controller chipset was pretty capable of Ultra ATA/100. Maybe I could mod the cable to introduce the short. Is such a mod safe? – cyanic – 2012-06-27T22:52:14.313

This looks like Ultra DMA 2 indeed (which you are probably referring to with original ATA). Modification will be safe but tricky and maybe you also need to remove the short on the blue cable connector as otherwise the cable would be out of spec. – Gurken Papst – 2012-06-27T23:02:36.267

Does pin 34 do anything other than signify Ultra ATA? Looking at some IDE specs it seems to be a diagnostic bit, but with the current configuration it seems there are no side effects of it being hooked up wrong to the drives. – cyanic – 2012-06-27T23:04:01.053

It doesn't signify Ultra DMA (Ultra DMA modes up to and including 2 work anyway) but the presence of a 80 conductor cable, that is required for Ultra DMA 3 and upwards. Pin 34 is also used for the PDIAG (Passed Diagnostics) signal, which is used for communication between the drives during initialization. While it looks like it works in your setup anyway, this is what I meant with out of spec. – Gurken Papst – 2012-06-27T23:19:48.070

Epilog: Instead of swapping the two connectors at the ends of the cable and still have it twisting like a pretzel, I decided to move the slave connector closer to the system side. Took the connector off (broke a clip in the process, lol), and clamped it back on with a plastic clamp. Xbox shows Ultra DMA Mode 4, and peak transfer as above is 13500 KB/s. So not a whole lot of difference. I hope the old holes (now covered with electrical tape) didn't affect performance. – cyanic – 2012-07-04T22:10:03.810

Asked: 2012-06-27T20:46:09.290

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Active: 2013-10-02T23:11:02.260