Performance SATA 1.5Gb/s controller and SATA 3Gb/s harddisk

1

Afaik it's no problem to use a SATA 1.5Gb/s controller with a SATA 3Gb/s harddisk (spindle, non-SSD) due to SATA backwards compatibility (ignoring Force150/OPT1 issues for now).

To my understanding the interface speed will be throttled to 1.5 Gbps in this case, but what I don't understand and want to know is: does this throttling affect the read/write performance of the harddisk?

Say, I have a SATA 3Gb/s harddisk which has a sustained data rate of about 65 MB/s.

This 65 MB/s is far away from the maximum transfer rate of even a SATA 1.5Gb/s (150 MB/s) controller.

Would using a SATA 3Gb/s controller yield a (significantly) better read/write performance with the given harddisk than a SATA 1.5Gb/s controller? And if so, why?

Jürgen Thelen

Posted 2014-03-04T12:27:31.717

Reputation: 113

1The read/write is limited by the hardware itself. SATA is just the data bus. If a HDD can only write 65 MB/s then thats the data cap of the bus itself. increasing the size of the bus won't change that fact. – Ramhound – 2014-03-04T12:43:12.220

Answers

2

It likely would (by about 8% or so) for one simple reason -- SATA 3Gb/s controllers typically support NCQ and SATA 1.5Gb/s controllers typically don't.

David Schwartz

Posted 2014-03-04T12:27:31.717

Reputation: 58 310

Keeping in mind that the Hard drive itself also has to support NCQ. – Lawrence – 2014-03-04T12:57:52.203

Almost all hard drives that support 3Gb/s SATA also support NCQ. – David Schwartz – 2014-03-04T12:58:47.100

True. I misread the original question. oops. – Lawrence – 2014-03-04T12:59:43.353

@DavidSchwartz: ah, now that makes sense, thank you. Is this by about 8% some standard rule of thumb, or from your personal experience? – Jürgen Thelen – 2014-03-04T15:43:00.263

Asked: 2014-03-04T12:27:31.717

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Active: 2014-03-04T12:36:23.327