ahci mode not working with ssd in windows 7

Scotspaul · 13 Feb 2011 at 03:54

Hi, need some help please, I just finished installing windows 7 onto my pc, i did have xp but did a clean install. I tried to set ahci mode before i installed, but kept getting errors / lock outs when i tried to boot. Have also tried to enable it via the registry edit work around, all it did was force me to reset my cmos to get windows to start again.
What i am i really loosing by just leaving the ide mode running? disk performance is still pretty close to what it should be for my disk (60gb OCZ Vertex 2e).
From what i can tell trim is enabled, so can i just leave it on ide mode without worrying?

chaparral · 13 Feb 2011 at 09:17

Don't know if this is of any help

How to enable AHCI in Windows 7 after Instalation:

There is one way to fix this, although you need to have knowledge of registry editing. The detailed steps from Microsoft are as follows:

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.

These steps are provided at your own risk and not suggested unless you know and understand the risks. You will want to make sure the controller driver and MB BIOS support this option before you enable it

chaparral · 13 Feb 2011 at 09:32

The SSD am using has faster write speeds in IDE mode then AHCI mode

IDE mode read = 244mb/s
IDE mode write = 144mb/s

AHCI mode read = 244mb/s
AHCI mode write = 89mb/s

wonko · 13 Feb 2011 at 09:45

I could be wrong but I thought you needed to be in AHCI mode to get trim working.

My crucial M225 runs garbage collection when idle, which means that running TRIM isn't vital, and I 'd expect your OCZ drive is the same.

Have you checked for bios updates for your motherboard? If your motherboard has more than one sata controller, have you tried attaching the ssd to a sata port off the other controller?

Supernaut91 · 13 Feb 2011 at 12:48

TRIM can run in IDE or AHCI.

wonko · 13 Feb 2011 at 12:56

Ah, ok thanks - you're quite right, it seems ide drivers can support trim, but not all do.

chaparral · 13 Feb 2011 at 13:01

Why do people what to run there SSD in AHCI mode when IDE mode is faster :confused:

DrBombcrater · 13 Feb 2011 at 13:15

chaparral said:
Why do people what to run there SSD in AHCI mode when IDE mode is faster

SSDs are designed to work best with AHCI and are generally much faster than way. NCQ, which is only available in AHCI mode, helps scattered read/write performance significantly. Getting lower speed test results with AHCI suggests either something is not quite right with your system or the SSD's firmware may be bugged.

chaparral · 13 Feb 2011 at 15:22

Deleted

Scotspaul · 14 Feb 2011 at 06:48

chaparral said:
Don't know if this is of any help

That was exactly what i did to try and enable ahci, and resulted in me resetting cmos to try and get back into windows.

I'm guessing i need to try and update the mainboard drivers ( its a gigabyte GA-73PVM-S2H ) and see if that helps.

Is it worth trying to install the ahci drivers in windows before i start?