User profile for user: MNissen
MNissen Author
User level: Level 1
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Enable AHCI inside Windows 10 inside Bootcamp?

I have a Mac Pro (Early 2009), 2 x 2.26 GHz Quad-Core Intel Xeon, 32 GB 1066 MHz DDR3, OS X 10.13.6.


I installed Windows 10, working and happy, in a 500Gb Samsung SSD using Bootcamp. Because I want to use DCS World, the flight sim. So far so good, then I put in a 1Tb SSD (Crucial) to hold the big DCS World install.


Testing the speed of the SSDs, I used AS SSD Benchmark in Windows.


See Image01.png. It says "pciide - BAD" in red.


Both SSDs read and write at about 220~230 MB/s. They should go nearer 500 MB/s.


Looking at Dr Google, I see that the answer is to enable AHCI and there are many solutions to do this. I've tried a couple involving regedit in Windows, but no joy.


The drivers I see inside the Device manager in Windows are shown in Image02.png


I'm asking if anyone knows a step by step method, to enable AHCI inside Windows 10, inside BootCamp for my SSDs ?


BTW, any ideas of accessing UEFI inside a Windows reboot, do not show that option to me, unless I'm doing it wrong...





Mac Pro

Posted on Apr 19, 2021 2:50 AM

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User profile for user: Calvin_BT
Calvin_BT
User level: Level 3
664 points

Posted on Apr 20, 2021 4:48 AM

You will need to modify the Master Boot Record of your Windows drive.

This workaround only works for Macs with Intel disk controllers. If you have Nvidia chipset, it will not work for you. You may confirm it in device manager of Windows.

First step is to make sure windows tries to load AHCI drivers after AHCI is enabled in boot loader. if you miss this step you will get a BSOD on booting windows and you will need to restore old MBR for windows too boot up.

Open your Windows registry editor and make sure “Start” Value in the following keys are set to 0.

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Msahci
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\IastorV
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Iastor

Also we need the modified MBR which you can download from here : patchedcode.bin

Put the patchedcode.bin on a USB stick which we can use later.

OK, We are done in Windows. Now we need to boot using a Linux Live CD or MacOSX Install Disk. both will work.

Put the bootable CD or USB stick into your computer and reboot.

When you hear the boot sound (the white screen appears) hold down the option (alt) key. you should get the option to boot from CD or USB stick.

Boot from CD or USB stick and Open a Terminal Window.

First lets get a backup from current MBR so in case of any problems we can roll back to it.

Also please note I am assuming your windows disk is /dev/disk0. if yours is different you may need to change it.

Put in your USB stick, change directory to it and run the following command :

dd if=/dev/disk0 of=backup.bin bs=512 count=1

it will make a backup from your MBR to backup.bin

now it is time to write the new MBR to disk :

diskutil umountdisk /dev/disk0
dd if=patchedcode.bin of=/dev/disk0 bs=440 count=1

All done ! now reboot into windows :

shutdown -r now

In Windows you should see windows installs the new AHCI drivers. also you may check that by looking into device manager.

Also I recommend you to download and install “Intel Matrix Storage Manager” to update your AHCI drivers to intel’s ones.

If anything goes wrong, you can revert back to old MBR by following commands in Terminal :

diskutil umountdisk /dev/disk0
dd if=backup.bin of=/dev/disk0 bs=440 count=1


[Edited by Moderator]

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User profile for user: Calvin_BT
Calvin_BT
User level: Level 3
664 points

Apr 20, 2021 4:48 AM in response to Calvin_BT

You will need to modify the Master Boot Record of your Windows drive.

This workaround only works for Macs with Intel disk controllers. If you have Nvidia chipset, it will not work for you. You may confirm it in device manager of Windows.

First step is to make sure windows tries to load AHCI drivers after AHCI is enabled in boot loader. if you miss this step you will get a BSOD on booting windows and you will need to restore old MBR for windows too boot up.

Open your Windows registry editor and make sure “Start” Value in the following keys are set to 0.

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Msahci
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\IastorV
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Iastor

Also we need the modified MBR which you can download from here : patchedcode.bin

Put the patchedcode.bin on a USB stick which we can use later.

OK, We are done in Windows. Now we need to boot using a Linux Live CD or MacOSX Install Disk. both will work.

Put the bootable CD or USB stick into your computer and reboot.

When you hear the boot sound (the white screen appears) hold down the option (alt) key. you should get the option to boot from CD or USB stick.

Boot from CD or USB stick and Open a Terminal Window.

First lets get a backup from current MBR so in case of any problems we can roll back to it.

Also please note I am assuming your windows disk is /dev/disk0. if yours is different you may need to change it.

Put in your USB stick, change directory to it and run the following command :

dd if=/dev/disk0 of=backup.bin bs=512 count=1

it will make a backup from your MBR to backup.bin

now it is time to write the new MBR to disk :

diskutil umountdisk /dev/disk0
dd if=patchedcode.bin of=/dev/disk0 bs=440 count=1

All done ! now reboot into windows :

shutdown -r now

In Windows you should see windows installs the new AHCI drivers. also you may check that by looking into device manager.

Also I recommend you to download and install “Intel Matrix Storage Manager” to update your AHCI drivers to intel’s ones.

If anything goes wrong, you can revert back to old MBR by following commands in Terminal :

diskutil umountdisk /dev/disk0
dd if=backup.bin of=/dev/disk0 bs=440 count=1


[Edited by Moderator]

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User profile for user: MNissen
MNissen Author
User level: Level 1
5 points

Apr 19, 2021 1:01 PM in response to Calvin_BT

Thank you.


I should note;


The SSD s are for Windows, but on the 500Gb SSD, I have a 55Gb OSX partition, with 10.13.6 on it, this is the OSX, I installed Bootcamp from, so it's 444Gb for Bootcamp.


I initially tried to clone the windows install, from the 444Gb SSD partition to the new 1TB SSD, using Winclone in OS X. It failed at the end, so I've just kept that SSD, as a second Bootcamp disk, with only the DCS World files on it.


The OSX disks are, two 1Tb, in a RAID 0, this is my start up disk, "MacTwo", there is a single 2Tb HDD which is a back up clone of MacTwo.




Apropos of nothing , I am quite happy to start again with the BootCamp process using the two SSDs if it will improve my DSC World speeds.


I am currently getting 'OK' performance at "medium settings" in the sim (20~25 FPS), using three monitors 23", 30", 24" with a AMD Radeon HD 7970 3072 MB card. Better performance (40~50 FPS) with only the 30" monitor.


Also I've read, that trying to get SATA 3 performance out of a SATA 2 system, may not be achievable. But if I can get closer to 375 MB/s, rather than the 220~230 MB/s I get now, I'll be a happy boy.

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User profile for user: MNissen
MNissen Author
User level: Level 1
5 points

Apr 23, 2021 1:26 PM in response to Calvin_BT

Well I did all of that.


But of the three Windows registry editor entries, only the 2nd one was there.


As I had changed a couple of entries (the names of which escape me), to 0, in previous attempts, I changed the 2nd one and proceeded.


HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Msahci (not there)

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\IastorV

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Iastor (not there)


So after rebooting "pciide - BAD" in red was still in the AS SSD Benchmark.


So I reverted to the old MBR and "Poof!" no more Windows.


Any hoo, I've done a complete reinstall of Win 8.1 upgraded to Win 10, on the 1Tb SSD, which is in bay one of the Mac Pro.


Previously the Bootcamp was on the 500Gb SSD in the 2nd DVD bay, which, I thought may have slowed things down.


So it's all back and working, DCS world is as before, "pciide - BAD" in red is still in the AS SSD Benchmark.



Calvin_BT, thanks for your efforts.

_____


An aside: has any one had any experience with one of these ?


OWC Accelsior S

Add a 2.5" SATA 6G Drive to your Mac or PC

Directly mount any standard 2.5" drive.

Up to 550 MB/s sustained speeds. Enhance SATA 3Gb/s systems with SATA 6Gb/s support.

Easy installation.

No drivers required.

https://eshop.macsales.com/item/OWC/SSDACL6G.S/



I have read that putting an SSD on one of these will get fast speeds, but it could be they are not suitable for booting Windows/Bootcamp from.


Any comments?

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