A number of years ago I came across an eSATA cable system known as eSATApd (5V/12V) DeLock was the first vendor I am aware of which sold these products. The key feature with this system is that it carries +12V with no mandated current limit. This makes it possible to power 3.5″ external hard disks from a PC without needing that pesky power brick.
Not DeLock or any other vendor produce enclosures that make use of this system, but that’s fine. They do sell the eSATApd connector and I’ve been modifying (in some cases, their own) enclosures for years to accept eSATApd power input.
Recently I upped the ante by modifying a 2 bay RAID enclosure (using RAID 0) to accept eSATApd so I could power the entire enclosure from the PC. As you can typically get 12V/3A across these cables this should not have been a problem.
Except now I needed 6Gb/s SATA in order to get the benefits from the increased performance of the RAID 0 array. Suddenly, I’ve got a bit of a problem: These cables do not work at 6Gb/s.
This wasn’t entirely surprising to me. The specification for SATA is pretty clear about cables: The correct cable is a distinctive 100Ω impedance, flat twinaxial cable, whereas the DeLock/LINDY cable is a fairly thin and flexible round cable.
Another point that SATA-IO are clear about, is that there is no such thing as a 6Gb/s SATA cable. Cables that were properly designed for the original 1.5Gb/s interface should work just fine for 6Gb/s.
Notwithstanding this, I’m already suspicious about the construction of these cables. Let’s take a look at this one:
As the DeLock cables I purchased are now pretty much useless to me, Let’s cut one open and see what’s in there:
Well that clearly isn’t a very SATA looking cable. What appears to be in here is a couple of foil shielded PVC coated pairs of the same kind of construction that would be used in an HDMI cable.
Allow me to get out my Paint-fu to draw a little diagram of the two styles of cable:
That’s a pretty significant difference in design.
But despair not (?) DeLock seem now to be selling a newer version of this cable, which I’ve got a couple of. It’s a lot bulkier, with two fairly rigid cores bonded together. Perhaps this newer cable works at 6GB/s? Why else would they change the design. The old design, being thinner and several times more flexible, was a lot nicer to use.
Nope. This cable also doesn’t work at 6Gb/s. The system in most cases can’t detect the drive, and when it does detect it, file transfers frequently fail.
So now I’ve got another useless eSATA cable. Let’s cut this one open and see what’s going on:
From what I can see, the core on the right is a “Powered USB” cable, this is typically used in conjunction with a specially designed connector for Retail/POS terminals which have a higher power requirement. This cable carries the +12V, +5V and USB 2.0, and is the correct type of cable for the USB half of this application.
The cable on the left is the one of interest as it carries the SATA signals. It appears to be of exactly the same construction as the previous edition of the cable – two foil shielded PVC coated pairs.
Whatever the reason these cables don’t work at 6Gb/s, they both have the same problem.
Success at last
After hours of frustration – I found a very interesting looking cable on the U.S. Amazon site. Sold by “Micro SATA Cables“, it’s the first I’ve ever seen which uses proper SATA cable, bonded to a power cable. This is what I was looking for. Fortunately Amazon U.S. ships internationally, a week later I got a couple to try out.
They work! Reliably sustaining the ~350MB/s my 2x6TB RAID 0 enclosure is capable of, and clearly surpassing the ~225MB/s limit of 3.0Gb/s SATA.
I don’t need to cut this cable open to know that it’s correctly designed. Aside from it actually working, the data wire is clearly labelled “Serial ATA”, and it also physically looks like SATA twinaxial cable.Posted in PC & Software
4 thoughts on “6Gb/s SATA 3.0 over eSATApd (12V/5V) cables”
Thank you for the read.
I was wondering (if you wouldn’t mind answering my query) if you know how much current an eSATApd port can allow for without disconnecting due to safety protocols.
There is no protocol. Current limit is either when the contacts, cable or whatever is feeding it burns out.
I wouldn’t push the 12v rail beyond 3A, or the 5v rail beyond 1.5A.
This looks great. I’ve been hunting for eSataPD enclosures for a long time. Really surprised me that it seems to be completely non-existent.
its a shame these aren’t common as mud with eSATApd being the defacto standard on pc motherboards instead of the much less useful eSATA