Compatibility VS AHCI on SSD

[PhoenixR]

Yesterday I tried to install a clean XP x64 on my T400 SSD and got BSOD. Changed AHCI to Compatibility and it worked, naturally. So I wondered - what's the real life benefits of the AHCI vs Compatibility on a ThinkPad with SSD, has anyone switched and noticed any considerable speed increase, better performance - is it worth it to go for a AHCI driver or it is all the same if to stay in Compatibility ?

[TPFanatic]

I truly think there's no noticeable difference from PC user standpoint. PC spends most its time idling.

If you had been a Business keeping a fleet of heavy-duty servers up to date operating at full capcaity for as long as possible, then any slight suboptimal differences in reliability or efficiency will show up on the Balance Sheet and the Bean Counter will order you to optimize electricty expenses.

Now none of this matters anymore.

If you want AHCI mode enabled

This thead on VOGONS.org dated 2025-01-15 seems to offer the least nonsensical solution.

https://www.vogons.org/viewtopic.php?t=104508

Greetings to all! I am writing this short guide in order to help anyone that wishes to install Ahci drivers and enable Ahci mode to a Windows Xp OS that has been already installed and is running in Ide mode.

I myself have spent a lot of time and effort trying to get the proper drivers installed and Ahci mode to work on my existing Windows Xp build and after unsuccefully trying every method posted online i finally had success with the following method, (found here: https://www.os2museum.com/wp/booting-windows-xp-or-not/) which i think is going to work on every pc already running Windows XP.

Diskclaimer: the drivers provided in step 2 are for an Intel based Sata Controller, but the procedure remains the same for any other type.

So here it is:
1. Boot normally in IDE mode
2. Unpack this WinRar file anywhere you like (which contains the best Achi drivers package for Windows Xp and covers almost any Intel based Sata controller, found here: https://winraid.level1techs.com/, if you have another type of Sata controller search the same site for it):

Filename
Generic 32bit Intel RST AHCI driver v11.2.0.1006 mod+signed by Fernando.rar
https://www.vogons.org/download/file.php?id=210009
File size
247.7 KiB
Downloads
72 downloads
File license
Fair use/fair dealing exception

3. From the contents of the unpacked archive copy iAstor to: Windows/System32/drivers
4. Execute the following CMD command:

Filename
Execute This On CMD.txt
https://www.vogons.org/download/file.php?id=210010
File size
113 Bytes
Downloads
88 downloads
File license
GPL-2.0-or-later

5. Add the following string to the registry (save the text document as a .reg file type and execute it to add it to your registry) :

Filename
Add this to the registry.txt
https://www.vogons.org/download/file.php?id=210011
File size
230 Bytes
Downloads
73 downloads
File license
GPL-2.0-or-later

6. Reboot your Pc, enter BIOS and change your boot option from Ide to Ahci mode
7. Manually add the Ahci driver through Device Manager in Windows
Done!

I hope this little guide will be helpfull and save anyone interested in the subject from unnecessary trouble, frustration and hours searching for the proper way to manage this.

Good luck have fun.

[PhoenixR]

Thanks TPFanatic, I felt the same. I think I'll stick with Compatibility for a while, mark system performance and then update the driver with AHCI and see if there's any performance difference just out of curiosity. I'll report with my findings.