Technical > Computer Hardware Help > [hard drive] AHCI or IDE mode? New build Win 7 64-bit

[hard drive] AHCI or IDE mode? New build Win 7 64-bit

AHCI with an SSD, yes.

reply to HarryH3
AHCI regardless. Even without an SSD, it supports hot-swapping on SATA provided you do it right. see more information on Koitsu's post here: »Re: [hard drive] How to read a damaged HDD?
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If we lose this freedom of ours, history will record with the greatest astonishment, those who had the most to lose, did the least to prevent its happening.

reply to pr1mo
RIF.

>>The drives are spinning-disk models.

reply to Krisnatharok
I don't see a real need for hot swapping drives outside of a data center. I can shut things down for a few minutes to swap a drive. I suppose it's handy if you use eSATA external drives.

Does AHCI really net anything in day-to-day use? (Perhaps just having the AHCI drivers already loaded in Windows would make it simple to clone a mechanical drive to an SSD and just reboot?)

Hopefully koitsu will come along shortly and enlighten us all. Sometimes I think he knows more about hard drives than the people that make them do.

He does.

You may never know when you have an HDD go bad (like I did in that thread) and need to plug the hard drive in via SATA after booting..

Just saying, there's no reason I can think of (which admittedly isn't much) to go IDE over AHCI nowadays.
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If we lose this freedom of ours, history will record with the greatest astonishment, those who had the most to lose, did the least to prevent its happening.

reply to HarryH3
This is somewhat of a tricky question to answer without getting into a long diatribe. The simple answer is that yes, use AHCI. The big advantages to AHCI with disks (referring to MHDDs or SSDs -- doesn't matter) is:

1. Proper nomenclature for hot-swapping
2. Command queueing (NCQ)
3. Generally no-nonsense disk geometries compared to IDE (meaning in most cases, you can take a disk partitioned on one AHCI system and stick it in another AHCI system and not worry about geometry oddities; with IDE this may vary)
4. A much more standardised protocol. Be sure to understand that AHCI does not replace, or necessarily have anything to do, with the underlying storage protocol (ATA) used by disks.
5. TRIM support (for SSDs only) -- though purely from a technical standpoint there is no reason TRIM cannot be done by the underlying storage drivers / kernel in IDE mode, but we know that with Windows apparently to get proper TRIM support you do need to use AHCI.

By "IDE" here, I should note I'm referring to both the "IDE Emulation" mode that some controllers have (e.g. your disks show up as classic Primary Master / Primary Slave / Secondary Master / Secondary Slave devices), as well as the mode where the controller operates via native SATA.

I should note that getting SMART stats off of MHDDs or SSDs is perfectly fine when using AHCI on Windows Vista or Windows 7. It's only "slightly" trickier on XP (just make sure with things like smartmontools you refer to your disks by either a drive letter with an association partition (e.g. disk 0 has C:, thus smartctl -a C:), or using the /dev/sdX nomenclature, e.g. smartctl -a /dev/sda rather than /dev/hda which a lot of people use. The latter will not work with AHCI in my experience).

There is also another advantage I've found with AHCI, at least in practise on Windows XP when you have a SATA-based ATAPI device (e.g. CD/DVD/BR drive):

In IDE mode, certain ATAPI operations (or possibly XP's ASPI -- yeah, lots of acronyms being thrown around here, sorry!) tend to "lock up" the storage subsystem entirely. I can easily reproduce the following situation: system becomes extremely sluggish when using something like DVD Decrypter to rip a CD (from E:) to an MHDD drive (D:) while trying to use the system for other things that are I/O-bound (e.g. launching Firefox from C: (SSD) takes literally 10-15 seconds). With AHCI mode none of this happens, and I'm about 99% certain that it's because there's a 1:1 association between port and device in AHCI mode, while (at least on my systems) IDE mode results in my SSD as Primary Master, ATAPI drive as Primary Slave, and my MHDD as Secondary Master.

Bottom line: use AHCI in Windows Vista or Windows 7, and if you can get AHCI drivers for your system in Windows XP, use it there too.

The only real reason to go with IDE mode is if you need to access your attached disks/devices in an OS that lacks AHCI support (e.g. MS-DOS 6.22, etc.). Don't misunderstand me though: you can absolutely use AHCI mode and, say, boot a CD that uses MS-DOS (such as a firmware updater, a disk utility program, etc.) and read files off an ATAPI device, but don't expect to be able to see disks in that mode. This is usually why when running things like Western Digital or Seagate's disk tools (via the bootable ISO method) that you need to switch your controller to IDE mode else they won't find any disks. That's honestly about it.

Finally: this is about transport protocols, not disks. I happen to know a lot about both, but just because a person knows a lot about disks does not mean they know a lot about transport protocols. For example I know some guys who know the mechanics of hard disks (physically) much better than I do, but if you started talking to them about ATA command protocol they wouldn't have a clue. :-)
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Making life hard for others since 1977.
I speak for myself and not my employer/affiliates of my employer.

Now THAT is a definitive explanation!

I genuflect in your general direction...

Thanks for the info. AHCI it will be.

reply to koitsu
Koitsu should be DSLR MVP.

Not sure what MVP is (I know what MVM is; it's in the FAQ), but if it's this kind of MVP then sucks to be me -- only sport I like is hockey and I don't play.
--
Making life hard for others since 1977.
I speak for myself and not my employer/affiliates of my employer.

reply to HarryH3
Where does one enable / disable AHCI or IDE? Is this in the BIOS? Would it be listed under any other name or label?

Yes, it would be in the system/PC BIOS.

reply to HarryH3
I do have to say I noticed in AHCI mode, the desktop responds better (quicker) than in IDE mode.
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Illegal aliens have always been a problem in the United States. Ask any Indian. Robert Orben

reply to koitsu
To get ACHI drivers we would need to see if the motherboard manufacturer has the drivers correct?

If we want to use ACHI is there issues with switching from IDE to ACHI without doing anything to the current hard drive - correct?
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Brian

"It drops into your stomach like a Abrams's tank.... driven by Rosanne Barr..." A. Bourdain

reply to bbear2

Yes that is it. Under the BIOS or UEFI, there is a setting on newer Mobos that you can enable it from. However you will need to reinstall if you do due to IDE boot partitions being incompatible with ACHI partitions.

Unless there is a Boot Fix program available. Anything I have seen looked like it was a bit iffy to use.So when you switch from IDE to ACHI be prepared for a boot error that says cannot find boot partion.

If your machine is already in ACHI mode then your ok. The IDE mode I am running currently due to my Backup App not supporting ACHI. But I am thinking hard to switch over due to what Koitsu said about XP and the system becoming sluggish with certain applications. Also there is performance enhancements in ACHI that improves over all speeds of your machine. (From all I have read)

reply to bbear2
Also it varies from Mobo Manufacturer to also Bios/UEFI coders.

reply to Tweakbl
Thanks for confirming and the additional boot reminders. But why is it under the RAID category? This seems to imply if you're not using RAID, then you don't get the AHCI choice.

When switching from IDE to ACHI or Visa Versa you will get a Blue Screen. The Error code is 0x0000007B (In Win XP) The only cure for it is as far as I have found, either A: Reset Bios/UEFI and call it a day, resigning yourself to IDE Mode or B: Reinstall with proper Drivers slipstreamed into the install disc (IN Win XP anyway, Newer versions of Windows should be ok, so you can just do a reinstall of the OS)

bbear2...no clue, depends so much on the Bios Coder and Board Manufacturer. There should be a few options in a drop down tab or something there to select IDE (Compatible/Enhanced) ACHI and maybe RAID but would think the RAID settings would be separate from the two others.