TR Forums

Hi,
I'm facing a rather bizarre issue. I have a WD 3 TB external drive which, on certain USB cables, can transfer files only at USB 2.0 speeds (in USB 3.0 ports, obviously). The same cables work normally at USB 3.0 standard when connected to other external drives and the respective WD drive works normally with different USB 3.0 cables. Can anyone tell me what is going on? Could it be that the controller of that WD drive does not recognize certain cables (they might be older, as they came with earlier drives) as USB 3.0?

Any correlation with cable length?

Theory 2: Maybe something that has to do with the connector. Sometimes I don't get stuff detected as USB 3, and I have to replug the cable on the PC side.

meerkt wrote:

Any correlation with cable length?

No, all cables are typical external hdd cables, around 50 cm each.

The only correlation is that (the two) cables which did not work at USB 3.0 with that particular drive came with some older Seagate and Adata external drives (I can recognize them after the particular shape of the connector's plastic sheath). But those cables function normally (as USB 3.0) when connected to other WD external drives.

Maybe something that has to do with the connector. Sometimes I don't get stuff detected as USB 3, and I have to replug the cable on the PC side.

It did not work for me. No matter how many times I replugged those 2 cables in question, they still work as USB 2.0 (the only connection is that the WD drive in question is fairly new, around 1 year old, while the faulty cables came, as I said, from different external drives and are much older).
Now I have cables who work well with that WD drive, so it's not really a big deal, but I would like to figure it out what is wrong, in order to decide whether to throw those suspicious cables away or not.

Sounds like a combination of marginal cables and a marginal USB implementation on the drive.

USB is not as finicky as HDMI but still not 100% consistent. I'd keep the cables, and just use them where they work well.

Only remaining ideas to try: different ports, and another computer.

just brew it! wrote:

Sounds like a combination of marginal cables and a marginal USB implementation on the drive.

Could you elaborate?

meerkt wrote:

USB is not as finicky as HDMI but still not 100% consistent. I'd keep the cables, and just use them where they work well.

Only remaining ideas to try: different ports, and another computer.

Already did that, same result.

Noldor wrote:

just brew it! wrote:

Sounds like a combination of marginal cables and a marginal USB implementation on the drive.

Could you elaborate?

If the two devices can't maintain enough signal integrity to maintain a USB-3 connection with each other, they'll drop back to USB-2 rates, which are slower but also less sensitive to the connection quality. Some devices are more finicky than others. Might have to do with cable length, cable shielding, an ever-so-slight looseness in one of the connectors, who knows. Or the control chip in the external drive isn't very good and readily drops out of USB-3 mode at the slightest glitch.

ludi wrote:

Noldor wrote:

just brew it! wrote:

Sounds like a combination of marginal cables and a marginal USB implementation on the drive.

Could you elaborate?

If the two devices can't maintain enough signal integrity to maintain a USB-3 connection with each other, they'll drop back to USB-2 rates, which are slower but also less sensitive to the connection quality. Some devices are more finicky than others. Might have to do with cable length, cable shielding, an ever-so-slight looseness in one of the connectors, who knows. Or the control chip in the external drive isn't very good and readily drops out of USB-3 mode at the slightest glitch.

The peculiar thing which had me scratching my head is that the WD external drive and the respective 2 cables don't maintain a USB 3.0 connection and drop to USB 2.0 only when paired with each other. The WD drive using other cables and the suspicious cables connected to different drives work just fine.
If the cables had proven faulty when connected to other drives, I would have thrown them away without any second thoughts.

Noldor wrote:

The peculiar thing which had me scratching my head is that the WD external drive and the respective 2 cables don't maintain a USB 3.0 connection and drop to USB 2.0 only when paired with each other. The WD drive using other cables and the suspicious cables connected to different drives work just fine.
If the cables had proven faulty when connected to other drives, I would have thrown them away without any second thoughts.

That's a common problem, and not just with USB-3. No guarantee the cables are even the problem, it might be the drive which isn't manufactured to spec or has a bad connection.

General rule is that if you found a combination that works, mark it for future use, and then keep an eye on that drive just in case the problem reappears under different circumstances, suggesting more things going bad.

High speed serial connections are very sensitive to cable quality, connector quality, and how carefully the designer of the electronics has laid out the PCB to minimize signal skew/reflections. Every little imperfection in any of the above degrades the signal. The combination of that drive, and the two cables that are giving you grief, just pushes it over the edge.

Just to give you a feel for how crazy things have gotten, for current high-speed serial protocols like USB 3.0 and SATA, there can be multiple bits of data strung out end-to-end INSIDE THE CABLE at any given instant. The bits actually propagate down the cable like a series of waves, where the distance between the crests of each wave is shorter than the cable length, for all but the shortest cables. The wave analogy goes further too - any slight imperfections in the signal path cause reflections (just like waves in a lake bouncing off of a rock sticking out of the water); these reflections distort the original signal, making it harder to decode the bits properly.

When I think about stuff like this, I am amazed things work as well as they do.

Do you think hat's a sign the drive could fail?

If I think more carefully, I believe I have experienced something similar before, as I recall that I have thrown away a USB 3 cable which was doing exactly the same thing, with a different drive, some years before - but at the time I thought the cable was simply defective, so I didn't split hairs.

just brew it! wrote:

When I think about stuff like this, I am amazed things work as well as they do.

QFT. That's why tech excites me so much. It's like working with miracles everyday and on top of that, a miracle that failures happen as less frequently as they do. The worst and most unreliable tech in PCs for me was floppy disks. You never knew when their time was up.

To the OP, why are you using different cables with your WD drive? The drives usually come with a pretty high quality cable.

Noldor wrote:

Do you think hat's a sign the drive could fail?

If I think more carefully, I believe I have experienced something similar before, as I recall that I have thrown away a USB 3 cable which was doing exactly the same thing, with a different drive, some years before - but at the time I thought the cable was simply defective, so I didn't split hairs.

Given the fact that WD external drives tend to have the USB controller integrated into the actual drive itself...I'd have a backup of it and/or not trust it anywhere near as much as before it behaved poorly.

Waco wrote:

Given the fact that WD external drives tend to have the USB controller integrated into the actual drive itself...I'd have a backup of it and/or not trust it anywhere near as much as before it behaved poorly.

It is not clear to me from this thread whether the problem developed over time, or existed from day 1. In any case, yeah I'd be a little leery of entrusting any critical data to this drive.

That said... USB 2.0 and USB 3.0 signals run over different pins in the connectors, using different pairs of wires. So my best guess is, if whatever is contributing to the problem on the drive end degrades further, worst case is (probably) that you'll lose USB 3.0 capability completely, but will still be able to retrieve the data at USB 2.0 speeds.

just brew it! wrote:

Waco wrote:

Given the fact that WD external drives tend to have the USB controller integrated into the actual drive itself...I'd have a backup of it and/or not trust it anywhere near as much as before it behaved poorly.

It is not clear to me from this thread whether the problem developed over time, or existed from day 1

That's because it's not clear to me, either.

Anyway, thanks for the feedback. I'm more inclined to think that there is nothing wrong with the drive per se, but, as you suggested previously, it's just that the signal integrity isn't always perfect if the drive and cable are not from the same manufacturer. I say that because I remember another such previous situation, when another USB 3.0 cable was functioning at USB 2.0 speeds: the cable was a Seagate and there is a good chance (75% I would say) that drive I've tested it on was also a WD. At that time, I though the cable was bad and I threw it away without looking into the matter, but if there are multiple occurrences which manifest themselves exactly the same, it might be a case of a mismatch from fabrication.

But it's not due to the length, because I've tested the WD in question with a longer (1.8 meters, Hama) cable which I use with my desktop and it functions at USB 3.0 (so the score is 2 - 2; 2 cables which work at USB 2.0, two which function normally at USB 3.0).

To the OP, why are you using different cables with your WD drive? The drives usually come with a pretty high quality cable.

Well, I can't use the exact cable a drive came with because I can't tell which those are. I can distinguish only between brands (Seagate, WD, Adata, etc) because the shape is different, but I can't tell which WD cable came with which WD drive, because they all look the same.
As to why I used a cable from a different manufacturer than the drive itself, it was just a happenstance.

Noldor wrote:

Well, I can't use the exact cable a drive came with because I can't tell which those are. I can distinguish only between brands (Seagate, WD, Adata, etc) because the shape is different, but I can't tell which WD cable came with which WD drive, because they all look the same.

Then try using any WD cable with the WD drive in question and see if the problem persists.

Everyone probably sources their cables from the same Chinese factories.