Tutorial : How to switch from IRRT to AHCI mode - E6400/E6500 (Vista)

The random red spike every 30 secs or so happens regardless of whether I'm using M-Audio, on-board audio, or no audio at all--happens even if the laptop's just sitting there, doing nothing.

I am using an external mouse--a Microsoft mouse--I will try not using it, see if that helps.

I can't use the onboard audio for serious work because I'm a public radio news producer--I bought my e6500 to be a mobile workstation for recording and editing radio content. Onboard sound won't cut it, for that kind of job.

Prior to my e6500, I was actually using an ancient Compaq laptop from 2000 or so. It had a 450 mhz processor, 160 megs of memory, but it actually worked well--I ran a very stripped-down version of XP on it, and it was extremely stable and reliable making recordings. It finally died, and I'm really surprised how much more stable it was compared to this brand-new e6500...

 

What puzzles me is that Intel states that the GM45 chipset ICH8M-E/ICH9M-E SATA RAID controller supports both AHCI and RAID, and that the Intel Matrix Storage Manager (and driver(s?)) supports both AHCI and RAID in RAID (IRRT) mode, and that you can't reconfigure the BIOS mode without crashing... and yet the Dell factory install allows it.

So, is there some other (less hack-like) way to mimic the Dell factory install when performing a clean install?

GK

 

Just to make sure I have this thought out:

1. Under win xp, I can apply the registry patch that will allow me to switch from IRRT to AHCI in the BIOS (with or without downgrading the Intel Matrix Storage Manger).

2. Can I then switch back and forth between IRRT and AHCI by just changing the option in the BIOS?

3. Under AHCI, am I correct in assuming that the eSATA port is still functional?


Thanks,
Harvey

 

I explained why in the original post but, when you change from IRRT to AHCI in the system bios, your SATA hardware ID type changes. Then when you boot into windows a stock install cannot enumerate (indent) the newly found AHCI controller because Vista's stock enum info predates GM45.

The reg key I attached to the tutorial simply adds the enum info so the OS can identify the controller.

The Dell stock image simply contains the same reg key. If you want to create an installable updated image with these enum keys, use something like Nlite to slipstream it into the Vista DVD then burn this to a new disc.

So this is not really a hack, you're just adding what's missing so the system can indentify the AHCI controller and proceed, without which it will bluescreen.

Hope this is maybe more clear.

 

1. Yes, I hadn't tried it in XP, but according to some of the other guys it works just fine.

2. Yes, since now both IRRT and AHCI enum ident keys are found in the registry the OS can identify either controller, communicate with the hard drive and start the OS as usual. You can change from IRRT to AHCI in bios as you please.

3. Correct AHCI (Advanced Host Controller Interface) contains all the modern features, NCQ, Hotswap, eSata, power saving features etc.

 

Thanks. I have ordered an E6500 (paid for by my company) and plan on doing the above so I can obtain max performance with the SSD and also image to an external HDD via eSATA.


Harvey

 

I follow. If I do a clean Vista install with BIOS set to AHCI, does Vista then recognize the GM45 AHCI controller? Or what?

I guess what puzzles me is that Intel says 'don't switch' and Dell proceeds to make it possible... so why doesn't Intel address/solve the issue... because AHCI could disrupt a RAID setup?

GK

 

Yes if you set the bios to AHCI and then install the OS, it enums as a generic AHCI controller and load the MSAHCI driver. Later when you install Intel's IMSM it further enums to the Intel ICH9M AHCI controller, sets the enum ID in the registry (only as AHCI) and loads it's own drivers. Later if you change to IRRT it will bluescreen because the registry contains Intel's AHCI enum info (or the reverse if you started out with IRRT instead). Hence the reason why we need to add this additional key later.

It's quite simple.

 

Perhaps the only reason Dell ships the BIOS set to IRRT (RAID) is for IRRT... so business notebook users have this backup/restore option. So if you don't intend to use that, then setting the BIOS to AHCI for clean installs could be preferable.

GK

 

I don't understand why you say that? could you elaborate?


so do you guys all agree that AHCI is faster than IRRT? does IRRT offer any advantages?