Admins eHow SysAdmin Tips & Tricks

Apple does all the dirty tricks to show the iSheeps that Apple is a superior brand and provides superior performance compared to competition, the last one I found is that it disables AHCI support for Windows on its hardware. By disabling AHCI (which you have already paid for it and Apple hardware has this feature) it forces Windows to use ATA controller disk drivers which is considerably slower than AHCI and has less features. for example you wont have TRIM support on your SSD disk on your Windows.
By doing so, Apple gives you this feeling that Windows is slower than Mac OSX on the same hardware.
Hopefully there is a workaround for this fraud of Apple. 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