ahci modes in biostar ami bios

thebudman · 02 Jan 2012

Hi i have a few questions regarding AHCI in my bios, First let me explain i did the Regedit tweak to enable AHCI but I'm confused as to what mode to use.

From my Bios manual Biostar A2+/TA790GX A2+

OnChip SATA Type
This option allows you to select the on-chip Serial ATA operation mode.
Options: Native IDE (Default) / RAID / AHCI / Legacy IDE / IDE->AHCI

SATA IDE Combined Mode
This option controls the SATA/PATA combined mode.
Options: Enabled (Default) / Disabled

I have it set to (AHCI) currently and i see a screen detects AHCI drives when booting and then boots windows, I notice in this mode under hard drive configuration i don't see any drives but it still shows it under boot options,

I tried the (IDE->AHCI) mode and I can then see my SATA hard drives show up in hard drive configuration and was still able to boot but i wasn't sure if this is the correct mode to use and if AHCI was enabled? or if both IDE and AHCI was enabled?, Or if it is some mixed mode? I'm Trying to figure out the difference between them 2 modes.

I disabled SATA IDE combined mode as i have no IDE drives in my system, I believe that is only needed enabled when i have IDE and SATA drives installed at the same time?

DustSailor · 02 Jan 2012

Bud,

Your manual should explain the difference. Unless you are using a RAID configuration, and your Motherboard can handle it, select AHCI.

You may need to install its drivers.

thebudman · 02 Jan 2012

That is a copy paste directly from my manual, it only gives me vague information, Done all that and have AHCI enabled, I just need to know the difference between the 2 ahci options in my bios not the raid,

essenbe · 02 Jan 2012

Sounds like a rather confusing bios. But, Dustsailor was correct in setting it to AHCI. In AHCI windows will install it's own AHCI driver (MSAHCI) or you can install AMD's AHCI driver. Unless AMD has improved it in the last year or so, Mocrosoft's AHCI seemed to perform better. You can tell which driver you have by going to device manager and expanding IDE/ATA/Atapi controllers. At the bottom of the listing should be an AHCI driver. If it is from Microsoft it is the msahci driver..

thebudman · 03 Jan 2012

Yeah it is confusing, My other board in my other pc is not half as confusing and it has better descriptions of what the options do, what i don't understand is what the options with the arrow does (ide->ahci does.

stormy13 · 03 Jan 2012

I'm wondering if that IDE->AHCI setting gives you the option to configure each controller in the "IDE Configuration" section (can come in handy with some SATA optical drives). Have you gone back to that section after enabling to see if something like that appears?

thebudman · 03 Jan 2012

stormy13 said:

I'm wondering if that IDE->AHCI setting gives you the option to configure each controller in the "IDE Configuration" section (can come in handy with some SATA optical drives). Have you gone back to that section after enabling to see if something like that appears?

Yes i do see my drives under configuration with that option set with all the same options like s.m.a.r.t, dma mode, etc, and can see all my drives listed, With the other modes i see no drives listed there.

I'm assuming it is still running in ahci mode as i see the drivers loaded in windows still and have the safely remove hard disk,

Weird is it shows C: drive as eject-able when running ahci, You wouldn't think you could eject the boot drive at least, I haven't tried it as the sound of doing that sounds like a bsod coming on lol,

DustSailor · 03 Jan 2012

The boot drive or OS drive shouldn't be disconnected as that is how you are running your OS to begin with. But I would think AHCI enables you to disconnect drives from the OS, as it enables hot-swapping: http://en.wikipedia.org/wiki/Hot_swapping

I would wonder if the IDE -> AHCI is a way to change IDE to AHCI in the BIOS without OS problems, as the OS usually only installs AHCI drivers if AHCI mode is selected before the installation of the operating system. But AHCI is the proper choice and it may even work better than ide -> ahci. Most boards don't seem to have this option. And you've done the registry edit to enable AHCI, so you should be fine

essenbe · 03 Jan 2012

If you go to device manager and look under IDE/ATA/ATAPI Controllers, at the bottom you should see some driver with AHCI in the name. From your description, it sounds like you have the Microsoft AHCI driver, MSAHCI. If that is there, you are in AHCI mode. I'm sure you will find it there or you wouldn't have the safely remove your hard drives option. As DustSailor said, one of the features AHCI has that IDE does not is hot swaping.