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Internal port multiplier for SATA III

Last response: in Storage
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August 26, 2013 5:53:58 PM

I have spent most of the day (and others off and on) looking for a solution. No joy.

I have an Asus P8Z77-V Deluxe MB. It has SATA III ports from Intel (Z77 express, and Marvell 9128). I have more drives than SATA ports.

I need a port multiplier that I can mount in the PC case and expand the number of attachable devices.

Target Requirements:
SATA 6.0GB/s source and destination ports.

    Not a PCI board - a standalone device that can be powered from a PC power supply. Or maybe an external power supply.


    Needs to support FIS/NCQ.


    4 port minimum. More is better.


    Really supports SATA III speeds.


Yes, I believe I understand port sharing. Yes I could consolidate drives (sort of, long term). Please limit your responses to the parameters provided. If there is nothing that fulfills the specifications; go for it.

Best solution

a b G Storage
August 26, 2013 6:45:23 PM

There is no such thing as port multplier for SATA. You can get an addational SATA CARD or SATA RAID card. Please look at the items in this link.
http://www.newegg.com/Product/ProductList.aspx?Submit=P...

I own this card and it works great.
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

This card is 2 lane, PCIe 2.0 (but goes into a 4, 8 or 16 lane slot) it is not PCI. It will provide the bandwith required for full SATA III speed. I have mine pluged into my PCIe 2.0 X16 slot.
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a c 878 G Storage
August 26, 2013 7:58:34 PM

if you get an multi drive esata enclosure you'll be ok. the esata on your motherbd is asmedia which supports port multiplication. The intel does not. the marvel does but is buggy from what I've read.
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a c 349 G Storage
August 26, 2013 8:01:38 PM

You've probably read of "port multiplier support" and got confused. That is a feature of eSATA ports. An eSATA port has only ONE connector. BUT with port multiplier support in its contro9ller chip, the port allows you to connect to it an external case containing more than one HDD. The data communication channel is still typically 3 Gb/s max, but it is shared by all of the HDD's in the external case. This is NOT part of any internal SATA port system, and is not what you seek.

The thing you want is a PCI bus card (navalweaponsofficer linked to one for a PCIe 2.0 bus) with a controller that supports 4 or more SATA ports. Don't know why you say you don't want PCI card.

You should be aware that, if you are using this for mechanical HDD's - that is, ones with spinning disks and moving heads), there are NO HDD's that can access their data as fast a the older SATA II (now called SATA 3.0 Gb/s) spec. The newer SATA III spec has twice the speed in its communications channel, and that can be used by some of the best SSD's. But NO mechanical HDD will ever reach those speeds.
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August 27, 2013 12:13:07 AM

Thanks for the responses. I have more drives than SATA ports (including SSD and ignoring speed).

There are pci cards that have two actual ports but support 4 physical devices through port multiplication. There are also standalone small boxes that take a single eSATA III input port and generate multiple physical ports using port multiplying. The little boxes are rather expensive and I would have to find a place to put them inside the case. And the only ones I have found will have the wrong connectors. I also believe it is irrelevant that a mechanical hard disk (not the ones that are all silicon inside) can't make use of the bandwidth of even SATA II. With FIS support on the controller, the attached devices may have overlapping processes. The cables are not just tied together. There is a controller between the input and multiple output cables. The bus multiplexing is controlled by this port controller and it shares the bandwidth between devices that need access. With buffering in the drives (RAM or embedded flash), you should be able to utilize more of the SATA bandwidth if you are using more than one of the shared port drives concurrently. I probably won't do that very often. But the whole point in my question is to have more attached devices in the PC case. But it would seem sensible to get SATA III to future proof a little bit. I do not build new systems all that often.

I have an external box of drives on eSATA that I use for a RAID backup drive. It is a port multiplier with some extra smarts for hardware RAID. A majority of devices I have seen seem to include RAID with the port multiplication. Which may have something to do with the cost.

Thanks popatim for the note on the controllers on my MB. I was looking for that information.
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a b G Storage
August 27, 2013 12:55:49 AM

How much does an eSATA port multiplier cost? The ones I have seen cost more than a decent PCIe SATA card and will suffer the bottleneck of accessing all drives through one port with a max bandwidth of 6Gbps. if you get a two lane or more PCIe 2.0 card you will have 10Gb of bandwidth available for your devices at a lower cost. The right add in controller card is not the bottleneck it used to be the card that I mentioned supports the full bandwidth of my vertex 4 and peaks with read speeds of 542 MBps which is just over half of the cards available bandwidth.

If you are dead set on using an eSATA port multiplier you can get eSATA to SATA cables and use them to connect the multier to the disks then just power the disks from the PSU.
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August 27, 2013 1:52:23 PM

Naval - I did some research on the chipset on the card your pointed out. I think I fumbled my earlier Newegg search. I do not remember seeing that one.

That is one of the newest Marvell chipsets. It is newer than the one on my MB. The one on the MB was probably picked because of another different port. The card you recommended has the caching feature. I was going to use that on my MB, but this newer chipset might have fewer bugs.

Thanks.
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July 27, 2014 8:08:18 AM

navalweaponsofficer said:
There is no such thing as port multplier for SATA.


Of course there is, its even officially in the SATA RFCs, but its optional and companies don't HAVE to give that option.

So i suggest you educate yourself before you give false answers
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July 27, 2014 8:09:14 AM

Paperdoc said:
You've probably read of "port multiplier support" and got confused. That is a feature of eSATA ports. An eSATA port has only ONE connector.


It is also used for internal SATA Ports, as there is actually NO DIFFERENCE between esata and sata.
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a c 349 G Storage
July 27, 2014 11:37:08 AM

Well, there are a few differences. Two I know of (and there are a few more) are:

eSATA specifically supports Hot Swapping, whereas plain SATA does not;

eSATA uses slightly higher voltages for the signals, plus requires receiver circuitry to accept lower voltages. Together, these allow longer max data cable lengths to reach external devices.

In fact, although those are parts of the official specs that are different, many mobo chip makers have included those eSATA features in their internal SATA ports anyway. The effect is that, in the majority of cases, the two port systems are NOT different, as Okay Dokey said. It's just that these added features in internal SATA ports are not guaranteed since they are not required in the formal specs. And the mobo specs will never tell you the details.

However, some digging did find these points. OP, your mobo has three SATA controller chips - one each by Intel (the main set of 2 grey (6 Gb/s) and 4 blue ports (3 Gb/s) ), Marvell (2 Navy Blue ports (6 Gb/s)) and ASMedia (2 Red ports (6 Gb/s)). The Intel website says specifically that their Z77 chipset supports all eSATA features in their mobo ports. Although it is not stated explicitly that this included port multiplier support, I'd say it's a good bet. I could not find a clear statement on the Marvell ports. The ASMedia website does indicate that many of their current SATA controller chips include port multiplier support. I'm sure all of them also support FIS / NCQ. So, there's a good chance that what you need at the computer end is already included in all your SATA ports. All you need, then is an external enclosure and (power supply) with an eSATA connection that includes port multiplier support in itself, so it can work with the computer's ports.

Which port to use? Well, today's HDD units can't even fill the data transfer capabilities of SATA 3.0 Gb/s. However, using port multiplier support in SATA means that one SATA channel is shared by two or more devices. So it is possible to saturate a SATA 3.0 Gb/s channel with 2 HDD's, and using more HDD's heavily might be done best on a SATA 6.0 Gb/s port.
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