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SATA 3 Mechanical HDD's

Last response: in Storage
July 11, 2011 11:11:27 AM


I'm currently building a new PC that will need high write speed on the HDD's.

Currently thinking of the storage below.


120Gb SSD SATA3 (exact model I'll decide on later) plugged into a SATA3 port.

Local Storage

3x 2TB SATA3 RAID 0 array.

Now my question is; should i "waste" using three more SATA3 ports on my motherboard with these mechanical HDD's? Surely they wouldn't be able to fully utilise that bandwidth, thus they should sit on my SATA2 ports, regardless of their own interface speed?

Any suggestions welcome.

More about : sata mechanical hdd

a c 279 G Storage
July 11, 2011 1:35:49 PM

Suggestion number one: Backup your data frequently. RAID0 with three drives is more than three times more vulnerable than a single drive, and data recovery from RAID0 is massively difficult.

Suggestion number 2: Just be sure that the three ports that you choose are on the same controller. I recommend the controller that's part of the chipset, not an additional controller like the Marvell that is found outboard on so many Intel-based motherboards. You are right; SATA 2 or SATA 3, you will get the same performance from the drives. Connecting an SATA 3 drive to an SATA 2 port gives you SATA 2 speeds, period.

Have you chosen the motherboard yet?
a c 104 G Storage
July 11, 2011 1:39:49 PM


Building a new rig is always fun.

First of all, the SATA III SSD for your OS is great. If you are looking for speed, you should consider the OCZ Vertex 3 SATA 6gb/s which has speeds of up to 475 MB/s, as noted in a recent comparison article of the most recent SSD's in Maximum PC.

Now, how you set up your secondary RAID 0 array, depends a lot on the MB you choose or are using. Some of the newer ones have 2 additional controllers for SATA 3Gb/s and SATA 6Gb/s. SATA 3Gb/s ports theoretically can handle 2400 Mb/s

RAID 0 Arrays have read and write speeds of x times the number of drives, so 3 drives could push 3 x 150 MB/s or 450 MB/s, possibly more..

So I'd put them on a 6Gb/s controller if one's available on your MB. Many of the secondary controller chips have just 2 ports on the controller, and have software capability of handling RAID 0, RAID 1. Possibly your were considering the addition of a SATA RAID add on card that could handle more than two HDD's
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July 11, 2011 1:47:39 PM

hi & thanks for responding!

i am not worried about data loss, the volumes on this RAID will be huge (4-6TB) but equally they will be very transient, and are deleted usually within 48-72 hours of initial write, a loss will be an annoyance but not a catastrophe.

all essential data sits in a NAS running RAID 1 (but let's not get distracted by my NAS)

anyway, back on topic, I usually stick to Asus hardware - was thinking about the Asus P8Z68-V PRO Intel Z68 for a motherboard, noted that it has 4x6Gb SATA's and 4x3Gb's, ability to support SLI (although i would only take 1 GPU initially)

so the main crux of my question is, do modern HDD's with 6Gb/s interfaces take full advantage of this new speed, or is it a gimick, (would i gimp my speed putting 6gb/s HDD's into 3gb/s mobo interfaces)

thanks for reading!

Best solution

a c 279 G Storage
July 11, 2011 1:55:02 PM

FiL said:

so the main crux of my question is, do modern HDD's with 6Gb/s interfaces take full advantage of this new speed, or is it a gimick, (would i gimp my speed putting 6gb/s HDD's into 3gb/s mobo interfaces)

Not so much a gimmick, as they are ramping up the controllers for when they can use them. No current mechanical HDD can benefit from SATA III over SATA II. But it's probably cheaper to make all SATA III controllers and not have inventory of both types.

So my answer is a resounding "No, they don't."
July 11, 2011 2:21:08 PM

thanks for this, very helpful.

so the only question that remains is;

Is the SATA bandwidth on an interface allocated *per interface* or pooled amoungst ports on a given controller?

as i want to use a RAID 0 array, would using 3 SATAII ports in raid0 give me theoretically 9gb/s bandwidth, or would it be 3gb/s load balenced between the three interfaces?

if the later i can see that I would be contrained by SATAII and should go for the SATAIII, or potentially an external card (as to not constrain the SSD)
a c 279 G Storage
July 11, 2011 3:44:44 PM

It's per interface; don't worry. Theoretically 9 gb/s among the three drives.
a c 415 G Storage
July 11, 2011 4:19:37 PM

FiL said:
so the main crux of my question is, do modern HDD's with 6Gb/s interfaces take full advantage of this new speed, or is it a gimick
It's a gimmick when they print "6 Gbit/sec" in huge letters on the ads and the packaging, but the choice to use the technology is not. The industry as a whole is moving towards SATA-III and the chipsets that support SATA-II are starting to be discontinued. This is exactly what happened when SATA-II was introduced - all SATA devices basically started using the new SATA-II chips even if they didn't require them.

Think of it like your mouse and keyboard: they use a USB 2.0 connection that can run at a theoretical speed of 60MByte/sec. Do they need this? No, they'd function every bit as well over a 1.5MByte/sec USB 1.1 connection. But nobody makes USB 1.1 chipsets any more so we get USB 2.0. In a few years mice and keyboards will probably end up using 500MByte/sec USB 3.0 connections.
July 19, 2011 10:21:02 AM

Best answer selected by FiL.