AHCI and IDE???

What are these things? And if I only have a single Hard Drive. Do I use ACHI or IDE? what is the difference. Also, could using AHCI with only one HD cause system stability problems? or the BIOS or randomly reset it self?

I am using Vista 64 with a single 750 WD Hard drive. I don't think I need RAID, and am a little fuzzy as to the purpose of RAID.

Thanks for your time and please forgive my ignorance. I HAVE looked into this problem on my own with little or no definitive success.
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More about ahci
  1. use IDE(IDE mode). This lets the Sata drive run without any special drivers. You loose hot swap and native command queuing.

    ACHI(Advanced Controller Host Interface) is for things like hot swap and native command queuing(more useful for servers).

    If you plan to hot swap drives later then ACHI is a good option, but requires a driver on windows install. You may be able to change it after windows is installed. I have not tried since i use raid anyway(and need a driver to install).
  2. @ Nukemaster

    So, if I set up my BIOS to use AHCI with the current OS does that mean I have to reinstall the OS and everything else under IDE settings? I dont care if I do, thats not a problem.

    Also, If I set up the BIOS to under AHCI settings and didnt install any seperate drivers to run the drive could that be why my updated F3 BIOS randomly reverts back to F1 BIOS? Because I didnt install the proper drivers during install the HardDrive doesnt work properly?
  3. You need to find out first if your HD will support the hot swap and native command queuing. before doing it otherwise it will be pointless... Maybe that's why you getting a negative feedback... If you switch without loading a driver there is a big possibilities that your operating system will not to detect your HD. GOOGLE AHCI FOR MORE INFO.
  4. The BIOS reverts issue doesn't relate to AHCI/IDE settings. I don't know why is that happening, but IMO it doesn't relate with AHCI/IDE settings.

    For the AHCI itself, do you really need it? Really the only advantage of AHCI is this hot swap things, and also this Native command queue (which I don't really understand what it is). These don't mean much for day to day activities for most users, except if you're running server.

    Better to reinstall the OS from scratch. Although I read somewher that you can do it without reinstall the OS. The trick is to install the driver while you're in IDE (under Windows) and the swap to AHCI after that. Dunno whether it's work, as I'm not trying it myself.
  5. Vista has the AHCI drivers in it from what I understand. It is highly unlikely that setting the drive for AHCI has any impact on the BIOS rolling back to an older revision. If you are running AHCI already then there is no reason to switch to IDE and vice versa.
  6. For swapping from IDE to AHCI if you are not worried about reinstalling you may as well try to see what it does. Worst case you reinstall. Backup files first....just in case...

    As for the bios changing from F3 to F1. well thats not normal at all. Does the board do anything during this time? Blank screen for a bit then restart? could it be restoring its default bios due to an error. I have never seen that. It does not have anything to do with IDE or AHCI.

    nel89, Its not the drives that need to support hot swap. When you hot swap a drive to write any cached data to the disk(same thing a disk has to do on shut down) and then windows stops accessing it and you can then remove it.

    Another way to get removable(hot swap) is to disable any caching[just disk cache, not system and other cache](caching of files uses a temporary location such as ram[99% of the time its ram since its fast] to hold a file before it is written to the drive...this can improve performance when writing lots of small files to a drive...windows will write it all to the drive in one shot, but its dangerous since if you remove the drive after it looks the files are there they are in fact not...and for a raid setup without a high end card...and power out can be BAD) so the drive and windows can be remove at any time(you still don't want to remove it while writing to it as this will cause a corrupt file). Windows does this to allow you to remove flash drives without using the safe remove icon.

    Back on topic
    Its the controller that has to support it...so the controller tells the drive....time to shut down...write your cache....good....tell user to take it out. Then the controller keeps an eye out for if a new drive in inserted.

    You can change this setting under your devices policy settings, but most hard drives are grayed out and set to write cache always, but its available for usb storage devices(Even hard drives)
  7. @nukemaster Nice informations dude :) I will use your tips on write cache. Guess I have to disable it for all my external/USB HDD.

    Yes, Zorg is correct, Vista has AHCI drivers by itselfs. So if you are with Vista you don't have much to worry. I'm assuming that you're on XP, my bad.
  8. its off my default of usb drives. i still like to play it safe with external hard drives since i am not sure if my cheap enclosure tells the drive to not use its own(since its my backup drive and all)...flash cards are just a yank it out and go....

    For usb drives its set by default

    For most hard drives its on. Intel has an extra option....even with my ups i just don't trust it enough....

    may be worth it on some benchmarks..


    All NcQ does is optimize data writing and reading so the head moves over data it needs as fast(spends less time doing nothing....) as it can....i do not like wiki, but it has a nice picture. Like you said...only needed for servers in most cases. and it can slow games down due the the fact that the drive needs to queue up its reads and writes to use this strategy and this adds latency.
  9. Nice info, yes I checked mine and it's on quick removal by default, so I don't have to change it.

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