# Slow SATA II harddisk?

## mayday147

I bought a Seagate SATA II 300MB/s drive and a Gigabyte MoBo supporting SATA II, wich give me this slow results:

```

localhost mayday # hdparm -tT /dev/sda

/dev/sda:

 Timing cached reads:   3256 MB in  2.00 seconds = 1627.47 MB/sec

 Timing buffered disk reads:  220 MB in  3.01 seconds =  73.11 MB/sec

```

```

localhost mayday # lspci | grep ATA 

00:1f.2 IDE interface: Intel Corporation 82801GB/GR/GH (ICH7 Family) Serial ATA Storage Controller IDE (rev 01)

```

 And this is my 2.6.20 kernel config

Should this speed be normal for this device?

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## NeddySeagoon

mayday147,

Looks pretty good to me.

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## mayday147

But isn't it supposed to be 300MB/s ?

 *edit*

BTW Is there any way of optimizing SATA disks, like hdparm for ATA ones?

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## NeddySeagoon

mayday147,

The SATA link speed is not the data rate limit on disk data transfers, its the head/platter data rate, thats what gives you a sustained data rate of  73.11 MB/sec. It will be lower as you move in from the outside of the disk.

SATA does not need optimising like IDE does. SATA was designed first, then implemented, so its a standard.

IDE was introduced by Compaq and different manufactuers added features over the years, it became a standard of sorts in its later years but all the different add ons were still in use, so it was too late.

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## mayday147

I understand. Thank you for your help.

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## blu3bird

300MB/s is the maximum rate the interface is capable off but your hard drive can just read with 73MB/s. Which is damn fast!

to the comparison: my (desktop) ide drive does 61MB/s  :Wink: 

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## mayday147

So, if your IDE drive does 61MB/s and my SATA II does 73MB/s, then how much SATA I does, as if I don't see much difference between your IDE and my SATA.

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## blu3bird

There is not difference. The inner core is exactly the same(some discs and reading heads). But your drive is probably newer than mine and they made some optimizations. IDE, SATA, SCSI, SAS, whatever is just how it is connected to your mainboard or controller.

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## NeddySeagoon

mayday147,

For a long time now, the data rate over the drive to motherboard cable has been more than the head/platter limit.

Data rate is not the whole story, there is also latency, which is the time to seek to find the data.

Its not shown in the hdparm test as sequential blocks are read and there is only the track to adjacent track latency, which is low.

SATA II introduces command queuing, which allows commands to be executed out of order to reduce the effect of latency.

SCSI drives have had this for a long time. It improves real world performance but you wont see it in hdparm.

For the record SATA II does not mean you have a 3Gbit interface. It is permitted but not required.

You will have all the other good things to reduce latency that come with SATA II

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## mayday147

Thank you both for your help, again.

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