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SATA cables: Is there a difference?

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SATA cables: Is there a difference?

Written on August 11, 2011 by Matt Bach

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Warning: Always look at the date when you read a hardware article. Some of the content in this article is most likely out of date, as it was written on August 11, 2011. Check out our more recent articles.

Introduction


Edit 2/11/2013: Due to the date of this testing and the fact that this question still comes up fairly often, we have decided to revisit this topic with more modern hardware in our SATA 3Gb/s vs. 6Gb/s Cable Performance (Revisited) article. Check it out to see if the results are any different using newer hardware and cables.


With the release of SATA III 6Gb/s, we have seen some confusion on the web regarding SATA cables.  Some claim that you need a specific SATA 6Gb/s cable to get the full speed of SATA 6Gb/s drives, while others say that there is no difference.

In the offical SATA-IO document "Fast Just Got Faster: SATA 6Gb/s", the following is stated:

The same cables and connectors used for current SATA implementations can be used to connect SATA 6Gb/s devices. SATA-IO recommends utilizing quality components to ensure data integrity and robust operation at the fast 6Gb/s transfer rate. Cables already at the threshold of 3Gb/s operating margins may experience lower performance than expected at 6Gb/s due to an increased number of resends.

In other words, as long as you are not using cheap knock-off cables there should not be any difference.  We prefer to have empirical data to back up these types of claims however, so we decided to compare a set of supposed SATA 3Gb/s cables against a SATA 6Gb/s cable.

Before running the speed tests, we cut open a set of cables to see if we could find any design differences.  The big things to look for at the number of wires and the gauge (size) of the wires.

Asus SATA 6Gb/s (Black) Asus SATA 3Gb/s (Red) Asus SATA 3Gb/s (Black) Intel SATA 3Gb/s (Blue)


In the pictures, the sleeved wires are all the signal wires, and the unsleeved are the ground wires.  You can see that all the cables have the same gauge of signal wire, although the Asus SATA 6Gb/s and the Intel SATA 3Gb/s both have an additional ground wire.  This is not for performance reasons, but simply due to the design of the cable.  Instead of having the cable in one piece, those two cables are more like two seperate cables fused together.  This should not have any effect on performance, which hopefully our speed tests will verify.

Speed Tests

To compare the speeds for each cable, we configured our test hard drive as a secondary storage drive and ran the benchmarks with each separate cable.  We used a very fast SSD SATA 6Gb/s drive on a SATA 6Gb/s port, so any loss of speed should quickly become evident.  The benchmark we used was CrystalDiskMark.

Test Hardware:

Motherboard Asus P8P67 Pro
SATA Controller Intel P67 SATA 6Gb/s
RAM 2x Kingston ValueRAM DDR3-1333 2GB
CPU

Intel 2500K Quad Core 3.3GHz

Hard Drive Intel SSD 510 250GB SATA 6GB/s
OS Windows 7 Ultimate 64-bit


With all that said, lets take a look at the actual performance of each cable.  All results are in MB/s.

  Asus SATA 6Gb/s (Black) Asus SATA 3Gb/s (Red) Asus SATA 3Gb/s (Black) Intel SATA 3Gb/s (Blue)
Sequential Read 464.2 464.0 462.7 460.5
Sequential Write 326.8 328.2 328.9 327.5
Random Read 512KB 314.6 314.8 315.3 315.1
Random Write 512KB 301.4 301.2 300.8 301.3
Random Read 4KB (QD=1) 19.8 19.8 19.8 19.8
Random Write 4KB (QD=1) 44.0 43.9 43.9 44.0
Random Read 4KB (QD=32) 80.3 80.1 80.2 80.1
Random Write 4KB (QD=32) 50.7 50.6 50.7 50.6


From these results, we can pretty conclusively determine that all of these cables are running at the full SATA 6Gb/s speeds.  There are of course some minor differences between the results, but they are all well within normal testing variations.

Conclusion

In conclusion, our testing has agreed 100% with SATA-IO's statement that SATA 3Gb/s cables will work perfectly fine with SATA 6Gb/s drives.  This wasn't much of a surprise to us, but it is always nice to have hard data backing up a claim.



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Jamie

Great stuff - thanks!

Posted on 2012-03-07 12:21:45
Greg Stanley

Funny how I was just completing a new build with an ASUS P8Z68-V PRO/GEN3 motherboard and, aside from the 6 GB/s cables included with the Intel 520 Series SSD I installed, I pondered about the black w/black connector head and black w/white connector head SATA cables included with the motherboard--i.e., which set was 3 GB/s rated and which was 6 GB/s rated because neither set were marked nor were they distinguished in the motherboard manual.  So, I called ASUS tech support and asked.  Guess what?...matching perfectly with the pictures in this article, the ASUS tech said the black w/white connection heads were the 6s and the black w/black were the 3s.  The main reason I went to all this trouble to ask is that I wondered which to use to connect up a couple of WD hardrives.  Well, well, well...according to this article, it really looks like it doesn't matter which cables you use.  it's the DEVICE that determines throughput capability.  If the DEVICE is 6 GB/s rated, use whichever cable you like....you'll still get 6 GB/s capability.  

Posted on 2012-03-10 21:41:05
68k_dude

Awesome work. Nice pics and some good wire stripping.

Posted on 2012-05-20 23:30:33
Mark

Thanks a lot for the info and the testing, it helps a lot :)

Posted on 2012-06-22 13:16:37
Willie

I was confuse on this matter. The info was great. You guys did a great job. THANK YOU

Posted on 2012-07-11 19:59:01

It may be a problem when you use some drive which can support more than 500MB per sec since for 3 Gb/s cables just guarantee only 384MB per sec

Posted on 2012-08-24 01:30:59

Unless you are trying to use super cheap cables from Ebay or somewhere like that, you shouldn't see any performance difference no matter the drive you are using. A wire is a wire, and as long as the gauge of the wire is correct, the end connections are good, and the right metal is used, there is no performance difference between one cable and another.

Posted on 2012-08-24 17:22:40
Green Tea

Not hardly....... These SATA and other" paired" wire runs are Hi frequency
transmission lines, with a "characteristic" impedance that is subject to, wire
type (solid or multi- pared twisted core), dielectric type, spacing, and proximity
to other conductive media (ground).. Much like an antenna feed....

Posted on 2014-05-12 20:57:14

Saturate the bus at its full spec' length; see what happens across a broad selection of 3 and 6Gb/s cables. 500MB/s = 4Gb/s. You need to hit >750MB/s to really test a 6Gb/s cable. Tiny differences in insulation thickness and capacitance make a proportionally bigger difference to signal quality the harder you drive the connection; it'll still *work*, but increasing error correction and data re-requests will begin to eat into the maximum bandwidth on a low quality (not necessarily inexpensive) cable.

I'd guess that: If a drive's read capacity is maxed at e.g. 500MB/s and a SATA cable is producing errors that require data to be re-sent, that (very recently read) data will still be in the drive's cache (assuming it *has* cache; apparently some sandforce-based drives don't use it at all: http://www.legitreviews.com/ar....

If the guess above is right, even though the cable is introducing a high error rate, as long as the error rate only slows the cable's data rate to something between 500MB/s and 750MB/s, you won't see any measurable difference at all in throughput from a 500MB/s drive because of the read buffer. You could be re-transmitting half your data and not know it.

I don't know enough about the SATA controller spec to say whether there's an additional buffer between the drive's putative cache and the cable itself that would amplify this effect, or even introduce it to the sandforce controllers mentioned above, but... "probably"?

This feels like a simplification of how the buffer actually affects throughput, but it's in the right ball-park.

Posted on 2013-01-28 19:40:13
Roland

Numbers speak.

Posted on 2013-06-16 18:37:37

The latch cables that Asus has been pushing are crap. This test not only proves the new connections are a gimmick but rip off. The latches pop off when you push and pull to remove them. The only purpose for them is to add to their bottom line in motherboards and drives and offer no benefit whatsoever

Posted on 2013-07-23 19:57:09

In our experience, the latches work great to keep the cables seated. This may not be a huge deal for users that build their own computers, but since we ship nearly every system we build they greatly reduce the number of times the cables come unseated in shipping. We build and ship hundreds of systems a month here at Puget Systems, and we have nothing but good things to say about SATA cable latches.

In fact, nearly every manufacturer (not just ASUS) now uses these latches. If you check out our updated SATA Cable article (http://www.pugetsystems.com/la... both ASUS and Intel cables now have these latches. And if you look online you'll find that most other brands (Gigabyte, Zotac, MSI, etc.) use them as well.

Posted on 2013-07-24 18:18:20
Leonardo Monday

XP crap just wasted 25 bucks on two cables to get the same speed ... hahha, damn tom share posts ...

Posted on 2013-09-03 19:18:52
Damian

Very kind of you to take the time to prove the theory and then explain it to the rest of us so clearly. Certainly gave me the reassurance I needed. Have just upgraded from a failing SATA II drive to a new SATA III drive without wasting money on a new cable thanks to you. Much appreciated.

Posted on 2013-10-19 17:08:09
JJtoob

Very interesting.

Posted on 2013-10-31 17:39:19
Alex

Thank you for taking your time and doing full test!

Posted on 2013-11-13 06:30:32
Kingfisher

Actually they are simply SATA cable not SATA I, SATA II or SATA III.

Posted on 2013-12-26 14:12:32
Akai Taiyo Martial Arts

Still suffering from the old PATA 40 vs 80 wire cable syndrome I asked myself the same question regarding SATA cables and could find nothing in the repair manuals or mother board books so I just used the old Asus SATA cables for the new hard drive, with only the best results. Thanks for all the work and the reassurance.

Posted on 2014-04-10 17:24:53
StockStalker1

I just got stuck with some terrible "Sata 3" cables off ebay. I was wondering what the hell was going on when I rewired my desktop and after power on immediately got a SMART error on a brand new 730 SSD (Intel stuff works perfect out of the box..always..period), had another SSD disappearing and reappearing, and then one of the SSDs in my RAID array was only running at 3gbs on a 6gbps SATA port which obviously slowed the entire array down to 3gbps * 2 speeds.

I don't know whether it was because I used round cables or because I used fairly long ones (18"), but $2 / cable isn't good quality stuff.

Posted on 2014-05-06 20:37:59

Round cables and 18" cables should both be fine, it was likely just that the brand of cable you received was not a very high quality brand. In fact, $2 per cable is actually more than we usually pay for a SATA cable. The cables we use here when a motherboard does not include enough cables are the $1-2 SATA cables from MonoPrice (http://www.monoprice.com/Produ.... We've never tried their colored cables, but the black ones we have had no problems with even though they are fairly inexpensive.

Posted on 2014-05-06 20:45:12
JustOnce

Thank-you. Well written and concise. Important information! Unlike a lot of the other crap on the web about technology.

Posted on 2014-07-25 00:55:35
RD Jim

This answered my question. I hope nothing has changed in three years. Hate to have to buy all new right angle SATA cables. Thanks for the testing!

Posted on 2014-10-25 03:47:06
Nick

Thank you!

Posted on 2014-11-26 16:30:13
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