I'm building a second system based on the components I built on two weeks ago, which include Gigabyte GA-P35-DQ6 and a pair of WD 500GB SATA drives, to name the affected components.

This time, based on reading that Windows 2000/XP is supposedly AHCI-capable, I went ahead and enabled it in the BIOS from the start of things after basic system check before installing an OS.

Windows Setup was doing its thing, that is, until I selected a drive to partition. At that point Setup terminated with the error "unable to find any drives". No problem, so I thought. I'll just disable AHCI and restart installation.

That's when my troubles began... The very next time I tried to boot the system, it would hang at "verifying DMI pool data" and >ASCI 127 characters would appear in random places on the screen.

I Googled the problem and read everything from bad floppy drives to bad hard drives to bad motherboard. Oh boy... I contemplatedd the possibility of an "infant mortality" failure and the prospect of an RMA.

Not being one to give up easily, I disconnected any hardware that wasn't required for BIOS POST. That included the hard drives. As soon as BOTH hard drives were disconnected, the system would POST and get past the DMI pool message and then complain about no disc. Now we're getting somewhere, I thought.

Next step was to reconnect one drive at a time and see which drive "failed". After exhaustive testing and rebooting with one and then the other drive, the problem persisted. Could BOTH drives have failed at the same time? Unlikely, I thought.

So I continue troubleshooting. Now I'm thinking it's either a bad motherboard or a power supply issue. So I moved the drives from the Gigabyte controller to the Intel controller connectors and rebooted. Once again, the problem persisted. Hmmm.. now what are the odds both controller chips are bad? Very slim.

After that, I figured it HAD to be a power problem, so I got out my DVM and measured 4.95, 12.04 and 3.29 volts on the red, yellow and orange wires going to the drives. Power's good--very much dead on spec.

So I Google some more, and finally run across something to do with corrupt master boot records. Some folks were fixing the hang on DMI pool with FDISK /MBR, from a DOS boot floppy.

So I tried it. With both drives connected. Then I rebooted. I got a slightly different hang--different "junk" characters displayed than usual. So I disconnected the second drive and rebooted. Now it booted into Windows setup. Ahah! That means I need to have only ONE disc in the system when I fix MBR. FDISK can't select which drive to fix, so the key is to have only one drive in the system. So I unplugged the first drive and ran FDISK /MBR again. Then I found I was able to boot into Windows Setup.

Here's what I think happened:

Contrary to what I read on the net, Windows XP setup does not natively understand AHCI protocol, so when it looked for the available drives, it could not find them, but this error was NOT non-destructive. Windows managed to corrupt the MBR on all drives attached to the controller that was in AHCI mode, causing the system to hang during DMI pool verification. The fix was to set up legacy IDE mode and fix the MBR on all attached hard disks, THEN installed Windows.

So if you are setting up a new system with AHCI-capable controllers, DO NOT enable it until you have Windows installed and then your motherboard chipset drivers for AHCI installed. Trying to jump the gun and be too advanced for the situation caused me a two-hour delay in setting up this machine, due to the inexplicable hang. Keep it simple, add the fancy stuff later, AFTER the drivers are installed.

I had suspected there may be an F6 install option for these drivers, but wasn't sure. You pretty much confirmed that it IS possible, with the drivers prepared for Windows Setup.

But you raised another question about the 150/300MB/S interface speed: Let me see if I understand this correctly: you're saying that it's possible that if you installed Windows in legacy IDE mode, that some drives will be stuck in 150MB/S mode, and if you install AHCI drivers during installation, the drives will be set to 300MB/S mode? Is that correct?
If so, then what are the remedies for drives installed in IDE mode, where the AHCI drivers were later installed in Windows after installation?
And which drives are affected? Will drive purchased this summer be capable of auto-switching to the higher speed?

Your problems had nothing to do with AHCI. Random characters on the screen and hanging during POST is a motherboard problem. You have:

- Corrupted or bad NVRAM/CMOS
- Buggy BIOS
- Electrical/connection problem - improperly seated PCI/PCIe card, bad cable, bad PSU
- Bad RAM

or some combination of the above.

On top of that, you had your drives connected to the JMicron controller, a controller that I've seen nothing but problems with on a number of different SATA drives. The JMicron controller isn't AHCI compatible or capable anyway. AHCI is Intel-chipset specific.

I've set up many systems with AHCI-native drivers during Windows setup using F6, all installed flawlessly. Nothing with AHCI is inherently broken or buggy.

Of course, ANY Windows setup that you do where you want to install Windows to ANY mass storage controller that is not legacy IDE-compatible will require the F6 procedure and a manufacturer-specific driver. This includes AHCI, RAID, SCSI, Fibre Channel, some SATA, and most proprietary controllers.

AHCI does not require any particular feature set or feature support from the hard drive. Any SATA drive can be installed on an AHCI controller - whether it implements SATA150 or SATA300, implements NCQ or not, etc.

There is much confusion with the purpose of the SATA150-force jumper on most SATA300 hard drives. This jumper is there ONLY for compatibility with very old chipsets that don't understand the speed negotiation of a SATA300 drive. In those rare cases (hooking a SATA300 drive to an old VIA or SiS chipset), set the jumper to force SATA150 operation. In all other cases, the jumper is superfluous. Install it if for whatever reason you want the drive to run at SATA150 speeds, remove it if you want SATA300. But the drive will operate properly in either case. Be aware that drives from different manufacturers default this jumper to different states. Western Digital ships their drives with the jumper removed (SATA300). Seagate ships their drives with the jumper installed (SATA150). Hitachi's don't even have a place for the jumper, so their SATA300 drives can't be used on those old chipsets, period.

I don't know where you dug up the FDISK /MBR information, but this had nothing to do with your problem, either. The BIOS put the random characters on the screen and hung way before the MBR was ever even looked at by the BIOS (the very last thing the BIOS does before attempting to boot). It isn't recommended to use FDISK /MBR to fix MBR problems anyway, FDISK installs a very old version of the MBR boot code that can be incompatible with the boot process of Windows XP and Vista under certain conditions.

It is always recommended to only have one hard drive physically installed in the system during Windows setup anyway. Depending on your motherboard BIOS, different drives on different interfaces and different controllers will be ordered in a way that might not correspond to what you want. For example, if you have a Raptor installed on the Intel SATA controller, a large SATA drive installed on the JMicron controller, and an old IDE drive installed on the IDE controller, you might want Windows to see the Raptor as C:, the large drive as D:, and the IDE drive as E:. But during Windows setup, it will assign drive letters based on the BIOS ordering, which you have no control over. If the BIOS identified IDE devices first, the IDE drive might show up as C: instead of the Raptor. If you subsequently install Windows to the Raptor anyway, your system drive might be drive D: or E: instead of C:. By pulling out all drives except the one you want to install Windows to, that leaves the BIOS no choice but to identify it as C:.

Just to add most seagate drives are jumpered to sata 150 by default(to maintain compatibility) and you just remove the jumper for 300.

To be honest, i have not seen any difference with 150 vs 300 since the mechanical drive is still slower then the speed of either interface.

Prettymuch whatever supremelaw and SomeJoe said (although I didn't catch the reference to JMicron controller in your original post).

AHCI is a [non-standard] controller feature and thus requires drivers, kinda like RAID. It allows you to do things like hot swap and NCQ that are otherwise unavailable.

This has been a very educational thread. Thanks for all the input.

SomeJoe, I'm convinced that fixing the MBR solved the problems. The system is working again and Windows installed without a hitch. The problem was definately a corrupted MBR.

It is possible that the MBR was part of the problem. A corrupted MBR can obviously do weird things, although to put random characters on the screen it would have to be really b0rked.

Instead of FDISK /MBR, you can use 2 methods to properly fix an MBR:

1. Boot the Windows XP CD-ROM, go to the recovery console, and use the FIXMBR command.

2. Use a zero-overwrite software like Darik's Boot and Nuke or Active@Killdisk, which will erase the existing MBR completely (as well as everything else on the disk). Then install Windows, it will write a new MBR during installation.

Thanks for the suggestion about using recovery console command FIXMBR to fix this properly.

Since the system is working properly now, is there any reason I should do this at this point? We're 36 hours into software installation and network configurations, so I'm leery of messing with the disk volumes at this point. If it ain't broke...

If the machine is now booting properly, then I wouldn't mess with it either. In all likelihood, when you finally got the Windows installation to work properly, it overwrote FDISK's MBR with it's own anyway.

http://en.wikipedia.org/wiki/AHCI

Over at the Asus camp, a lot of people are having problems to install Windows in P5K-Premium in all the storage modes (IDE, AHCI and RAID).

http://vip.asus.com/forum/view.asp [...] uage=en-us

The F6 step to load in the storage driver does not work at all. Seems the only way so far is to set the jumper to 150 MB/S.

I have a different but seemingly related problem.

Specs:
- Gigabyte GA-965P-DS4 (Rev. 1.0) - with F10 BIOS (currently the latest)
- Three HDDs: Western Digital 250GB - WD2500KS (wanted to RAID, but gave it up...)
- Core2Duo E6700
- Vista Ultimate 32bit

Problem:
I'm trying to install a clean Vista installation, so I delete all partitions, plug all three HDDs to Intel’s SATA ports, and switch on AHCI in the BIOS settings.
I ran the installation, used the "load drivers" option to load Intel’s “F6” drivers, and created a C: partition on the first hard drive. All went well, and Vista loaded. I worked with it a bit, and installed all latest motherboard drivers (chipset, SATA etc…)
AND THEN - I created a new partition on the second drive using Window's Disk Management (4GB, NTFS, full format, label "VistaSwap" - I wanted to put window’s pagefile there), rebooted and - wham, the computer doesn't boot. It gets stuck on the screen where the Intel BIOS recognizes the hard drives (is this called POST?). You guessed it - it gets stuck exactly on the second drive - the one I created the new partition on.
I tried this twice, and both times I got the same problem.
It seems the partition Windows created did something to the drive that caused it not to be recognized correctly by Intel's BIOS.
The only way I found to get out of this mess was to: 1)disconnect the drive 2) change BIOS setting from AHCI to disable 3) reconnect the drive 4) erase all partitions using Windows XP installation CD 5) try again…

Some basic questions:
1) Is there some minimum partition size I'm not aware of? (I thought it's 8MB, and that 4GB is way ok)
2) Should I always create the partitions with another program, and not trust Window's Disk Management? (For instance - Intel's Matrix Storage Manager? I have always used Window's Disk Management in XP, and it worked fine thus far)
3) Is there a way to update the Intel Matrix FW that isn't via a normal BIOS update?

I guess there are other options I didn't think about - Help

Found the problem.
I disconnected my 2nd drive and used my 3rd drive to tryout the "minimum partition size" theory. I started by creating a single partition on the entire drive, which worked great. Then each computer restart, I deleted that partition and created a new and smaller one.
10,000MB worked, but 6,000MB didn't. So as far as I can tell, there's a minimum partition size limit to Intel's 965P chipset, at least in AHCI mode.
btw, if anyone happens to reach this page due to searching for WD2500KS, you'd probably want to read this:
http://www.behardware.com/art/imprimer/624/

Everyone wants AHCI and I can't figure out why. Unless you want RAID, NCQ or hot swap, then there is no reason to set AHCI. Maybe people just want to make things more complicated and aggravating.
Am I missing something here?