Enabling AHCI for SSD under Win7 BootCamp on Macbook Pro 2011

Question

I've just installed a new Samsung 830 256GB SSD and have configured BootCamp with Lion and Windows 7.

Under Lion, I have installed Trim Enabler.

Under Windows 7 I have installed the Samsung (Wizard) software that came with the SSD. In this software I've applied all of the recommended optimisations under 'OS Optimisations', however, the Samsung wizard software is informing me that AHCI is not enabled at present and for best performance, this should be enabled.

I'm not sure a) what implications there are if it's left disabled (will it affect the lifespan of the SSD or is it purely a speed thing?) and b) if there is a way under BootCamp for an Early 2011 MacBook Pro to have AHCI enabled?

I was also concerned that if AHCI is not enabled, perhaps TRIM won't be enabled either? However, I did run a tool which I found online that said that TRIM was enabled on this Windows 7 install (despite AHCI not being enabled).

This is my first SSD drive so am not very familiar with the technology, terminology and best practices etc.

Solution 1

TRIM does not depend on AHCI mode and is also available for IDE. However, it may depend on the drivers you are using.

If you use your SSD in IDE or AHCI mode together with the Windows 7 native drivers, TRIM should work. However, using IDE you will miss some AHCI-specific features which may affect your drive lifespan. You can find a benchmark with a short summary here and here.

Here you can find a guide to installing specific AHCI drivers for Windows/BootCamp on a 2010 Mac Pro.

You can check if you have TRIM enabled in Windows 7 by using this command with administrator privileges:

fsutil behavior query disabledeletenotify

Possible results:

DisableDeleteNotify = 0 (Windows TRIM commands are enabled)
DisableDeleteNotify = 1 (Windows TRIM commands are disabled)

Solution 2

AHCI is not required for TRIM. However the Samsung drive can que commands and in order to use that you need AHCI enabled. (It will however work fine without AHCI, just a fraction slower)