That AHCI mode again: more insight required

[forumjoe]

In a reply to a topic I raised about a month ago, Lsdmeasap advised that I change the running of my single SATA2 HDD from IDE mode to AHCI mode. Whilst I still don't agree with him that AHCI will necessarily give me enhanced speeds over SATA IDE mode, an issue with my system has arisen where possibly the ability to do hot-swapping of HDDs could be useful. I've no need for, or any intention of, using RAID, incidentally. So, I'd appreciate some insight from others on this.

The impression given by my motherboard's manual is that if you want to run in either AHCI mode or RAID mode, you can only do this by installing the OS - in this case, WinXP- as an F6 install. I'm not sure, though, whether this notion has come about simply by a poor translation of the manual.

So, what I'm needing to know is whether, when the Intel H55 chip is onboard, AHCI mode is totally independent of RAID mode. That is, can you successfully move straight to AHCI mode from IDE mode by simply making one or two changes in the BIOS? If you simply want the advantage of hot-swapping but don't wish to go RAID, do you still have to do an F6 install?

For me, hot-swapping would be advantageous to something I now wish to do with my system, but is still not 100% essential. However, if the change in mode can be done easily, I may give it a try.

Mobo: GA-P55-US3L.
OS: WinXP SP3.

[F5BJR]

*
You can use only AHCI if you have make your installation with the good driver

Because you have a motherboard with 2 diffents sata ports ( INTEL and JMicron ) you can use all mode IDE / AHC I / RAID after a little  change :

If you have installed with INTEL in IDE mode ...

1 - disconnected your disk to the INTEL port and connect to the JMicron

2 - restart and modify your BIOS for JMicron in standard IDE mode , INTEL in AHCI

3 - start WinXP , requiert at this time the good INTEL AHCI / RAID driver , install this

4 - stop you computer and reconnect your disk to the INTEL port

5 - at this time because your have installed the good driver you can start without problem in AHCI mode

**

Pierre

[Dark Mantis]

Yes you can certainly use AHCI without anything to do with RAID. What you will need to do though is make some registry edits before enabling it in the BIOS.
Also I would agree with Lsdmeasap regasrding the performance increase. You certainly should see a speed increase on the read/write throughput.

How to change IDE mode to AHCI after OS installation.

1.Exit all Windows-based programs.

2.Click Start, type regedit in the Start Search box, and then press ENTER.

3.If you receive the User Account Control dialog box, click Continue.

4.Locate and then click the following registry subkey:
HKEY_LOCAL_MACHINESystemCurrentControlSetServicesMsahci

5.In the right pane, right-click Start in the Name column, and then click Modify.

6.In the Value data box, type 0, and then click OK.

7.On the File menu, click Exit to close Registry Editor.

After this you’ll have to restart your computer, go to BIOS and enable AHCI. When you log in to Windows again, you’ll notice the installation of drivers for AHCI. Another restart will be required to finish the driver installation.

[Lsdmeasap]

Those registry edits only easily apply to Windows Vista or Windows 7, for XP a clean install is easiest, XP can be a huge hassle.   Some have success by just updating the driver in device manager to Intel AHCI driver or MS AHCI Driver, but I've never done it personally and I've heard the outcome go both ways.

Or you could use an old outdated program to enable RAID Mode, this will setup the correct drivers and registry entries, and then you can switch the BIOS to AHCI mode instead of RAID once you install the updated RST program mentioned below.
http://mike.geek-republic.com/software/raidfix/

If you use that I highly suggest you update to the latest RST Drivers and programs right after you get it going though, then switch BIOS to AHCI
http://downloadcenter.intel.com/SearchResult.aspx?lang=eng&ProductFamily=Chipsets&ProductLine=Chipset+Software&ProductProduct=Intel%C2%AE+Rapid+Storage+Technology

You may also need to do a manual registry edit after installing the latest RST, before you switch to AHCI

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\IaStorV << Set start type to 0
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\msahci << Set start type to 0


A clean install using F6 to install drivers from a floppy disk, or a clean install of XP with slipstreamed drivers would be best though, and possibly easier for you to do.

[Dark Mantis]

Oh yeah, I forgot that you were using XP still. Sorry.

[forumjoe]

Oh, that's a shame. I'd been hoping that it was just going to involve a simple and perhaps reversible Registry mod. Jeeeez, for me, I don't think the revised advice is going to be worth following through. I'll stick with IDE.

Lsdmeasap and DM, would you say that the detailed modifications you've now given above apply only to Gigabyte motherboards, or could similar mods work with mobos of other manufacturers? I'm asking because someone on a non-Gigabyte forum to which I contribute is interested. If these mods are universal, would you mind me pasting the details you've given into the other forum? It's a forum that discusses the old Ghost 2003 backup application.

[Dark Mantis]

The mods to the Windows registry are universal so please feel free to post them.

[forumjoe]

The respondent on the other forum has asked me to ask you (that is, DM and Lsdmeasap) if you've tried using the OSDTool (TBOSDT Pro) with WinXP for installing AHCI drivers after changing the BIOS to AHCI.

[Dark Mantis]

For my part no I haven't, in fact I haven't tried very much along those lines with WinXP at all. I will have to leave Lsdmeasap's anwer to him but I would be surprised if he hasn't experience of it.