# Why AHCI driver Used When Sata Controller is in IDE mode?

## dman777

If my Sata Controller is in IDE mode, why is the ahci driver being used? 

```

        *-storage

             description: SATA controller

             product: SB700/SB800 SATA Controller [IDE mode]

             vendor: ATI Technologies Inc

             physical id: 11

             bus info: pci@0000:00:11.0

             version: 00

             width: 32 bits

             clock: 66MHz

             capabilities: storage pm ahci_1.0 bus_master cap_list

             configuration: driver=ahci latency=32

             resources: irq:22 ioport:ff00(size=8) ioport:fe00(size=4) ioport:fd00(size=8) ioport:fc00(size=4) ioport:fb00(size=16) memory:fe02f000-fe02f3ff

```

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## Jaglover

Because you are lucky? I have a box here that has no AHCI choice in BIOS because of some stoopid patent issue (although hardware is AHCI capable).

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## dman777

That's good to hear  :Smile:  But I'm trying to figure out the logic/contradiction in this....the mode is IDE and the driver is not IDE...the driver being used is ACHI. Shouldn't the ATA driver be applied and used?

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## Jaglover

Basically, it may be possible your BIOS tells the controller is IDE (needed for Windows installs) but still leaves AHCI mode available.

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## NeddySeagoon

dman777,

Switch the BIOS to use AHCI mode.  IDE mode is intended to be used once only, by Windows users that need to install the AHCI driver.

As such, the performance in IDE mode is often dreadful.  e.g, no DMA.

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## PrakashP

I know this thread is old..., nevertheless as far as I saw the kernel contains a quick to switch the controller (AMD southbridges) from IDE to AHCI mode. lspci still shows IDE mode as the device id isn't affected by the quirk.

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