# [SOLVED] SATA Hdd max dma mode is set at UDMA/33

## VanFanel

Hello there, Gentoo friends!

Back to some system optimizations and learning, I've been trying to get HDD performance up, as itn't enough for HD-video playback on my mac mini 2009 system.

First things first, here's what dmesg has to say about how my SATA HDD is configured by the kernel on boot:

```

[    0.321722] ata1: SATA max UDMA/133 irq_stat 0x00400040, connection status changed irq 21

[    0.321726] ata2: SATA max UDMA/133 irq_stat 0x00400000, PHY RDY changed

[    1.044514] ata1.00: ATA-8: FUJITSU MHZ2120BH G1, 00810009, max UDMA/100

[    1.045055] ata1.00: configured for UDMA/100

[    1.056522] ata2.00: ATAPI: PIONEER DVD-RW  DVRTS08, Q81B, max UDMA/33, ATAPI AN

[    1.056891]  sda:<6>ata2.00: configured for UDMA/33

```

As you can see, my /dev/sda HDD is configured for UDMA/33, wich is kinda slow, as it seems to support UDMA/133 (see previous lines).

hdparm is not use with SATA disks, as you may know, so dmesg is al I've to test the UDMA mode my HDD is configured for.

The relevant lspci info for this machine is:

```
  

00:0b.0 IDE interface: nVidia Corporation Device 0ab5 (rev b1)

```

I'm using the AHCI SATA support option in kernel. No SSF needed, I believe.

Also note I'm on linux-2.6.30-gentoo-r6.

Any ideas to activate/force full UDMA/133 support?

RegardsLast edited by VanFanel on Sat Jan 09, 2010 5:14 pm; edited 1 time in total

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## Monkeh

Your drive is correctly configured. The 'sda' in the last line should not be there (I'm not sure what causes it, but it's not relevant). Your drive will never achieve the 100MB/s speed it's configured for.

On a sidenote, Bluray video for example has a maximum data rate of 54Mbit/s, or 6.75MB/s. So unless you're dealing with ridiculously high bitrate video, your HDD is not your bottleneck.

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## eccerr0r

Yeah it looks like a kernel threads issue. scsi-disk detection was getting ready to print out the sda partition table I think, but half way through printing the sda partition table, SATA decided it wanted to print out the configuration of your optical drive...and the two got jumbled with broken semaphores...

Penalties of parallel initialization...

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## VanFanel

You guys are right: I've been conductiing some tests and it seems to be well configured...

Thanks a lot for your ideas and responses  :Smile: 

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