What is the maximum throughput of a SATA cable?

[0pTicaL]

It just crossed my mind that no one has asked this question. What is the maximum throughput of a SATA cable?

12Gb/s? 24Gb/s? 48Gb/s? Is there a limit?

 

[StalkeR]

SATA - 1.5 Gbit/s
SATA 2 - 3.0 Gbit/s
SATA 3 - 6 Gbit/s.

StalkeR.

 

[whs]

Depends where it is attached and what it is attached to. A Sata2 port can run at 3Gb/sec and a Sata3 port can run 6Gb/sec. But most Sata devices cannot keep up.

A spinning disk may read up to 800Mb/sec and a fast SSD may do 5Gb/sec.

 

[GeneO]

Don't know. I am sure the quality varies so it would be hard to put a limit to what they are capable of transferring at without error. They are only guaranteed to deliver what they are rated for and I think that is the best information you will be able to get.

 

[Layback Bear]

I don't understand this but. When I run my ssd on sata 3, 6.0 it's slower than a sata 2 at 3.0. Sata 3.0 is Marvel and sata 2.0 is Intel. AHCI or IDS. In my mind what every they are rated at might not be what you get. I don't remember where I read the test but the cable quality for 3.0 and 2.0 really didn't make any difference.

 

[0pTicaL]

Maybe I should rephrase it a little.

For example, you cannot use a 18AWG extension cord on a 20A circuit. You need a thicker cable.

Regarding SATA cable itself, what is the maximum throughput the cable can achieve before it requires a whole new SATA cable? (and yes I already know there is no difference between SATA1,2,3 cables, they are all the same and that is not my question)

SATA - 1.5 Gbit/s
SATA 2 - 3.0 Gbit/s
SATA 3 - 6 Gbit/s.

StalkeR.

No that's just the SATA spec and it's revisions. I'm talking about the SATA cable itself.

Depends where it is attached and what it is attached to. A Sata2 port can run at 3Gb/sec and a Sata3 port can run 6Gb/sec. But most Sata devices cannot keep up.

A spinning disk may read up to 800Mb/sec and a fast SSD may do 5Gb/sec.

Again that's the SATA spec. I'm curious what speeds the cable itself can sustain.

I don't understand this but. When I run my ssd on sata 3, 6.0 it's slower than a sata 2 at 3.0. Sata 3.0 is Marvel and sata 2.0 is Intel. AHCI or IDS. In my mind what every they are rated at might not be what you get. I don't remember where I read the test but the cable quality for 3.0 and 2.0 really didn't make any difference.

You're not alone, when I asked this question elsewhere I get the same answers. Everyone starts explaining to me the speed of the SATA spec and it's revisions which I'm fully aware of and a simple Google search or Wiki will tell me all I need to know.

What I want to know is, how fast can the SATA cable, the cable itself sustain? Not what it's connected to, or what SATA spec it belongs to.

 

[TVeblen]

Hey! Hard questions make my brain hurt!

I am not an electrical engineer, and I apologize to electrical engineers everywhere for any over generalizations contained in the following post.

I believe the theoretical throughput of an electrical signal through a copper wire is infinite - that is: in a perfect environment (absolute zero, pure copper, etc) all of the power/signal could travel at the speed of light. Problem is we do not have a perfect enviroment - far from it.

Because of the impurities in the copper itself and imperfections in the manufacturing process we have to deal with resistance (ohms), and because we are operating in an electrical environment we have to deal with interference (EMF's and such). So it gets complicated fast.

In a simple explanation, there is a "sending unit", the "conduit", and "receiving unit". That is where the standards come in. The three parts, made by 3 different manufactures have to work together within those standards in order for the system to work. When designing the sending and receiving units, deciding what the minimal power level necessary to meet the standards and compete in the marketplace, the manufactures rely on the minimal specs of the "conduit" manufacturers in the standards. Because everyone is "pushing towards the bottom" there is not a lot of room for error.

So while a cheaply made SATA cable may meet the standards (barely) it will produce much more resistance and interference between the sending and receiving units (SNR) in a particularly electrically noisy environment which will then result in errors. When errors happen the S&R units will react by slowing down until the signal becomes clear enough to use without errors.

By using high quality copper in the manufacture of wire, using a higher AWG wire, and using techniques like twisting pairs and shielded jackets, the quality of the signal in a particularly noisy environment can be greatly improved and therefore the speed through the conduit can be greatly increased.

Long answer short: "It depends"!

 

[Layback Bear]

Sorry for any misunderstanding on my part. I think this is what you are looking for.

Maximum PC | Is Your SATA Cable Slowing Down Your Data Transfers? Max PC Investigates

 

[GeneO]

I don't understand this but. When I run my ssd on sata 3, 6.0 it's slower than a sata 2 at 3.0. Sata 3.0 is Marvel and sata 2.0 is Intel. AHCI or IDS. In my mind what every they are rated at might not be what you get. I don't remember where I read the test but the cable quality for 3.0 and 2.0 really didn't make any difference.

The Marvell controller is not very fast - the Intel SATA2 controller is better for 4k random reads and writes. The only thing the Marvell can do a little better than Intel SATA2 is sequential reads. The Intel SATA3 is much better than the Marvell on all counts.

 

[GeneO]

I did understand what you are asking, but I don't think you can find an answer, and if you do, it will depend on the manufacture of the specific cable since all they need to do is perform at the SATA2 or SATA3 speed. The manufacturer probably has some idea but probably really doesn't know and won't have measured its limit. It isn't like anyone can test it on SATA8 for instance