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Wikimedia sata2 vs sata 3

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August 16, 2011 6:41:22 PM

Hello, what's the difference between sata2 and sata 3 hard drives?

More about : wikimedia sata2 sata

a c 503 G Storage
August 16, 2011 8:53:39 PM

There's no difference between a single SATA2 and a single SATA3 hard drive.

Hard drives cannot spin fast enough to saturate a SATA2 port, let alone a SATA3 port.

If you had 4 SATA2 drives in RAID-0 vs. 4 SATA3 drives in RAID-0 you would start to see differences in performance.
a b G Storage
August 17, 2011 5:26:49 AM

This is not true, newer SSDs can saturate a SATAII port. The RAID anology does not make sense either as SATA speeds are on a per device basis, not a bus basis as is the case with SCSI where all devices on a channel would share bandwidth. I good quality SATA RAID controller will do more than 600MB/sec with enough spindles and PCIe lanes.

Simply put SATA III only starts to make sense if you're using high speed SSD in excess of 300MB/sec
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a c 503 G Storage
August 17, 2011 5:44:49 AM

tokencode said:
This is not true, newer SSDs can saturate a SATAII port.



We were talking about hard drives, not ssd's. :-)
a c 98 G Storage
August 17, 2011 4:19:44 PM

The best performance I've ever got from any HDD was 2-Samsung F3 1TB in RAID 0, and it peaks at 140MBps, or less than half of the SATA II 3.0Gbps limit for 1 drive.

Dereck47 is right. Don't spend the extra money on a SATA III 6.0Gpbs drive. The difference between them is only in burst rates, which is insignificant.
a c 277 G Storage
August 18, 2011 1:52:19 PM

Gray80 said:
Hello, what's the difference between sata2 and sata 3 hard drives?

While all of the above discussion is correct, the basic answer is that SATA 2 hard drives have a controller that conforms to the SATA 2 specifications, with a maximum transfer rate of 3 Gbit/sec. An SATA 3 hard drive will have a controller that has a maximum transfer rate of 6 Gbit/sec.

As noted above, spinning-platter hard drives cannot sustain transfers of over 3 Gbit/sec, so they do not benefit from an SATA 3 controller. Many SSDs can benefit from an SATA 3 controller, if it is attached to an SATA 3 port on the motherboard. So why do manufacturers put SATA 3 controllers on slow HDDs? It's not for the ability to advertise "Blazing 6 Gb/sec transfer speeds." It's really because it costs them less to make and store only SATA 3 controllers and use them on all of their drives, rather than running production lines for both types of controllers and warehouse both types and so forth.


Note: If you attach an SATA 2 controller to an SATA 3 port, or an SATA 3 controller to an SATA 2 port, you get a perfect SATA 2 connection. SATA 3 is backwards-compatible.

Why is the word "Wikimedia" in the title of this thread?
a c 503 G Storage
August 18, 2011 6:28:06 PM

WyomingKnott said:
So why do manufacturers put SATA 3 controllers on slow HDDs? It's not for the ability to advertise "Blazing 6 Gb/sec transfer speeds." It's really because it costs them less to make and store only SATA 3 controllers and use them on all of their drives, rather than running production lines for both types of controllers and warehouse both types and so forth.


That makes perfect sense. I always thought it was for the advertising. :D 
November 30, 2012 6:19:59 PM

WyomingKnott said:
While all of the above discussion is correct, the basic answer is that SATA 2 hard drives have a controller that conforms to the SATA 2 specifications, with a maximum transfer rate of 3 Gbit/sec. An SATA 3 hard drive will have a controller that has a maximum transfer rate of 6 Gbit/sec.

As noted above, spinning-platter hard drives cannot sustain transfers of over 3 Gbit/sec, so they do not benefit from an SATA 3 controller. Many SSDs can benefit from an SATA 3 controller, if it is attached to an SATA 3 port on the motherboard. So why do manufacturers put SATA 3 controllers on slow HDDs? It's not for the ability to advertise "Blazing 6 Gb/sec transfer speeds." It's really because it costs them less to make and store only SATA 3 controllers and use them on all of their drives, rather than running production lines for both types of controllers and warehouse both types and so forth.


Note: If you attach an SATA 2 controller to an SATA 3 port, or an SATA 3 controller to an SATA 2 port, you get a perfect SATA 2 connection. SATA 3 is backwards-compatible.

Why is the word "Wikimedia" in the title of this thread?

Then it won't make any difference whether I install my new SATA 3 HD on a SATA 2 or SATA 3 port?
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