Are all SATA cables the same?

TVeblen wrote in
:

On 2/7/2013 10:17 PM, Metspitzer wrote:
On Fri, 8 Feb 2013 03:01:33 +0000, Mike Tomlinson
wrote:

En el artículo , The Daring Dufas the-
escribió:

So the SATA III drive will work in a computer with a SATA II
controller and doesn't care about the speed limit of the controller
because it will never be able to transfer data faster anyway? O_o

Yes. You need SATA3 for SSDs.

The latest crop of 4Tb hard drives (1TB per platter) have SATA3
interfaces, but it's pretty pointless because their maximum
sustained transfer rate is still only about 160MB/s, which is well
within SATA2's 300MB/s.

This drive says 6Gbs. Is that not supposed to be the transfer rate?
http://www.newegg.com/Product/Produc...82E16822148840


It's marketing. It says it has a 6Gbps interface, and that is provably
true, but it remains that the maximum transfer rate of the drive will
come nowhere near that.

There is one true fact listed that might benefit from a SATA3
interface: "SATA 6Gb/s interface optimizes burst performance"
But I doubt even the burst rate of a spinning drive will reach 3Gbps.


If the disk has a nice big internal cache, it will for short bursts
with pre-fetched data, use the full speed of the sata link.

On 2/7/2013 11:37 PM, Sjouke Burry wrote:
TVeblen wrote in
:

On 2/7/2013 10:17 PM, Metspitzer wrote:
On Fri, 8 Feb 2013 03:01:33 +0000, Mike Tomlinson
wrote:

En el artículo , The Daring Dufas the-
escribió:

So the SATA III drive will work in a computer with a SATA II
controller and doesn't care about the speed limit of the controller
because it will never be able to transfer data faster anyway? O_o

Yes. You need SATA3 for SSDs.

The latest crop of 4Tb hard drives (1TB per platter) have SATA3
interfaces, but it's pretty pointless because their maximum
sustained transfer rate is still only about 160MB/s, which is well
within SATA2's 300MB/s.

This drive says 6Gbs. Is that not supposed to be the transfer rate?
http://www.newegg.com/Product/Produc...82E16822148840


It's marketing. It says it has a 6Gbps interface, and that is provably
true, but it remains that the maximum transfer rate of the drive will
come nowhere near that.

There is one true fact listed that might benefit from a SATA3
interface: "SATA 6Gb/s interface optimizes burst performance"
But I doubt even the burst rate of a spinning drive will reach 3Gbps.


If the disk has a nice big internal cache, it will for short bursts
with pre-fetched data, use the full speed of the sata link.


That's what I was assuming about the internal cache memory. Now I'm
wondering about the data rates of hybrid drives where the SSD is melded
with a mechanical disk drive. ^_^

TDD

TDD

On Thursday, 7 February 2013 04:19:57 UTC+8, Metspitzer wrote:
I know there are SATA2 and SATA3 SSD drives. Are the cables
different?

Check out this review:
http://www.maximumpc.com/article/fea...c_investigates

On Thu, 07 Feb 2013 23:02:13 -0500, TVeblen
wrote:

On 2/7/2013 10:17 PM, Metspitzer wrote:
On Fri, 8 Feb 2013 03:01:33 +0000, Mike Tomlinson
wrote:

En el artículo , The Daring Dufas the-
escribió:

So the SATA III drive will work in a computer with a SATA II controller
and doesn't care about the speed limit of the controller because it will
never be able to transfer data faster anyway? O_o

Yes. You need SATA3 for SSDs.

The latest crop of 4Tb hard drives (1TB per platter) have SATA3
interfaces, but it's pretty pointless because their maximum sustained
transfer rate is still only about 160MB/s, which is well within SATA2's
300MB/s.

This drive says 6Gbs. Is that not supposed to be the transfer rate?
http://www.newegg.com/Product/Produc...82E16822148840


It's marketing. It says it has a 6Gbps interface, and that is provably
true, but it remains that the maximum transfer rate of the drive will
come nowhere near that.

There is one true fact listed that might benefit from a SATA3 interface:
"SATA 6Gb/s interface optimizes burst performance"
Correct
But I doubt even the burst rate of a spinning drive will reach 3Gbps.
A SATA 3 spinning drive might burst faster than 3Gbps. I might even
keep up this speed for a bunch of blocks being read from the drive's
cache. Might even be able to maintain the rate for a few blocks
being written or, in unlikely case, for the same track being written
several times pieces in just the right order.

On the other hand, the data rate within a single transfer always be
6Gbps.

On Thu, 07 Feb 2013 07:03:23 -0500, TVeblen
wrote:

On 2/7/2013 6:58 AM, TVeblen wrote:
On 2/6/2013 3:19 PM, Metspitzer wrote:
I know there are SATA2 and SATA3 SSD drives. Are the cables
different?


The specification for the CABLE in SATA2 and SATA3 are the same.

The one new difference is positive locking clamps on the connectors of
new cables.

The issue of good quality vs poor quality cable continues from SATA2.
While the wires are all 26g, the quality of the copper and the amount of
shielding are different from manufacturer to manufacturer.

Either Maximum PC or Tom's Hardware did a test of SATA cables about a
year back to see if there was any difference in performance between
regular SATA cables and "SATA3" cables. They even jerry-rigged a 24 ft
long cable and tested that to. The result: unless you are splitting
hairs - not much.


I mis-remembered. It was 6 feet, not 24!
Here is the article:
http://www.maximumpc.com/article/fea...c_investigates
I would think that the most important problem would be data errors on
the cables. These will be corrected by retransmission and probably
the data is buffered someplace, so cables causing only 1 mission
in 10000 you won't even see a speed difference. Even for much higher
error rates you would only have some overhead and a retransmission of
some number of blocks with no rotational delays, so not much slowup.

On the other hand, many drives record such errors in SMART data that
is not easily resetable, if at all. This leads at least some SMART
analyzing programs to forever after say that the drive has "warning"
SMART status.

In particular, I have a
Seagate ST3200064NS drive with
"(C7) Ultra DMA CRC Error Count" of 10 and
a Seagate ST32000641AS with a count of 3, as well as about
6 other drives with counts of 2 or 1.

(I think that the errors happened when I was operating the drives
outside of a system and bumped into something while a test was
running. In any event, the cable that was used in the test
is no longer connected to the drives which are now inside of
systems and in most cases connected to another adaptor.)

I looked at the Maximum PC article and didn't see any SMART data,
which to me would have been the most interesting thing after not
seeing any drastic reduction in throughput.

On 2/8/2013 7:50 AM, wrote:
On Thursday, 7 February 2013 04:19:57 UTC+8, Metspitzer wrote:
I know there are SATA2 and SATA3 SSD drives. Are the cables
different?

Check out this review:
http://www.maximumpc.com/article/fea...c_investigates


That is a very good article. Thanks!

On Thu, 07 Feb 2013 22:17:17 -0500, Metspitzer
wrote:

On Fri, 8 Feb 2013 03:01:33 +0000, Mike Tomlinson
wrote:

En el artículo , The Daring Dufas the-
escribió:

So the SATA III drive will work in a computer with a SATA II controller
and doesn't care about the speed limit of the controller because it will
never be able to transfer data faster anyway? O_o

Yes. You need SATA3 for SSDs.

The latest crop of 4Tb hard drives (1TB per platter) have SATA3
interfaces, but it's pretty pointless because their maximum sustained
transfer rate is still only about 160MB/s, which is well within SATA2's
300MB/s.

This drive says 6Gbs. Is that not supposed to be the transfer rate?
http://www.newegg.com/Product/Produc...82E16822148840

But you'll only actually see that when transferring from the drive's
cache.

On Fri, 8 Feb 2013 03:03:19 +0000, Mike Tomlinson
wrote:

En el artículo , Loren
Pechtel escribió:

There's nothing out there that can max a SATA3 yet but he said all he
has is a SATA2--and that will limit transfers with a good SSD.

Yes, and he also said "I bought a new hard drive with 6Gbps". We're
talking about his hard drive, not an SSD.

I've seen people use "hard drive" to refer to a SSD.

On Fri, 08 Feb 2013 19:56:08 -0800, Loren Pechtel
wrote:

On Thu, 07 Feb 2013 22:17:17 -0500, Metspitzer
wrote:

On Fri, 8 Feb 2013 03:01:33 +0000, Mike Tomlinson
wrote:

En el artículo , The Daring Dufas the-
escribió:

So the SATA III drive will work in a computer with a SATA II controller
and doesn't care about the speed limit of the controller because it will
never be able to transfer data faster anyway? O_o

Yes. You need SATA3 for SSDs.

The latest crop of 4Tb hard drives (1TB per platter) have SATA3
interfaces, but it's pretty pointless because their maximum sustained
transfer rate is still only about 160MB/s, which is well within SATA2's
300MB/s.
Some people use port multipliers, so there is interference even with
two
drives at 300MB/s, perhaps in RAID or disk cloning operations.

Three drives multiplexed would definitely see the interference
whenever 3 drives were busy, but most users would find 4 spinning
drives multiplexed to be fine as long as the didn't try to clone
two multiplexed drives. (I think having 3 RAIDed spinning drives
sharing a port on a 300MB/s port would be fine.)

This drive says 6Gbs. Is that not supposed to be the transfer rate?
http://www.newegg.com/Product/Produc...82E16822148840

But you'll only actually see that when transferring from the drive's
cache.

wrote in message
...
On Thursday, 7 February 2013 04:19:57 UTC+8, Metspitzer wrote:
I know there are SATA2 and SATA3 SSD drives. Are the cables
different?

Check out this review:
http://www.maximumpc.com/article/fea...c_investigates

Great article.
Thanks.

--
Jan Alter