640GB Western Digital Caviar Black WD6401AALS HD Tune Result

[Oversized Rooster]

Originally Posted by geokilla

Is there a difference between with ACHI on and ACHI off? I have a WD6400AAKS and I believe ACHI is disabled in the BIOS. The AAM value is set to 254 though and my access times were around 13s. I'll check the AAM values and the ACHI when I get home.

Also, my speed spikes down a couple times during the benchmark. Is that normal?


Those are some amazing speeds that you're getting with the Black. What's the hard drive used for?

AHCI allows the SATA drive to be used with specific SATA-native commands instead of IDE emulation. It doesn't necessarily add transfer speed.

Your speed can spike down during the benchmark - that isn't a flaw of the HD. This simply means that some process or program read or wrote to the HD during your testing which "diluted" your benchmark. For a clean benchmark run, try to kill all un-necessary processes using Task Manager.

The only reason why my WD6401 benchmarks have no spikes is because my system files are on another HD, so I can truly "dedicate" the HD for benchmarking. I use my WD6401 drives for storing my massive music collection, program CD ISOs, some videos, digital camera picture gallery, torrents, web site development, etc.

All installed programs, games and the system itself reside on my VelociRaptor. When I format my system, I can just backup everything to my 2 WD6401 drives and the WD5000AAKS so I never need to "burn backups".

[Eagle Eye]

Advanced Host Controller Interface - Wikipedia, the free encyclopedia

The Advanced Host Controller Interface (AHCI) is a hardware mechanism that allows software to communicate with Serial ATA (SATA) devices (such as host bus adapters) that are designed to offer features not offered by Parallel ATA (PATA) controllers, such as hot-plugging and native command queuing. The specification details a system memory structure for computer hardware vendors in order to transfer data between system memory and the device. As of June 2008, the current version of the specification is v1.3.[1]
Many SATA controllers can enable AHCI either separately or in conjunction with RAID support. Intel recommends choosing RAID mode on their motherboards (which also enables AHCI) rather than the plain AHCI/SATA mode for maximum flexibility, due to the issues caused when the mode is switched once an operating system has already been installed.[2]
AHCI is fully supported out of the box for Microsoft Windows Vista and the Linux operating system from kernel 2.6.19.[3] NetBSD also supports drivers in AHCI mode out of the box in certain versions. OpenBSD has had an ahci driver since OpenBSD 4.1. FreeBSD supports AHCI as well. Older operating systems require drivers written by the host bus adapter vendor in order to support AHCI.

Enabling AHCI in a system's BIOS will cause a 0x7B Blue Screen of Death STOP error (INACCESSIBLE_BOOT_DEVICE) on installations of Windows XP where AHCI/RAID drivers for that system's chipset are not installed - i.e. boot failure. Switching the chipset to AHCI mode involves changing the BIOS settings. Usually, manual installation of new drivers is required before enabling AHCI in BIOS.[4] Alternatively, a "Repair" installation with the appropriate driver loaded during the setup process usually corrects the problem.
For Intel chipsets (for example, Intel ICH9) drivers are available from either an OEM motherboard or computer manufacturer. For the Intel versions, the driver must be loaded before loading the OS (by pressing F6 as setup starts, then using the floppy disk when prompted).The Intel drivers will work for both XP and Vista. Also, in the case of ICH9, an unsupported method to enable AHCI on ICH9 is available.
When attempting to install Windows XP or a previous version on an AHCI-enabled system, setup will fail with the error message "setup could not detect hard disk drive..." since no drivers will be found for accessing the SATA controller/s. This problem can be corrected by either using a floppy disk or by slipstreaming the appropriate drivers into the Windows XP installation CD, or by turning on IDE emulation in the BIOS settings if it's available (usually labelled COMPATIBILITY or ACPI).
Enabling AHCI in a system with Windows Vista already installed will result in a BSoD if SATA was configured in IDE mode during Vista's installation. Before enabling AHCI in the BIOS, users must first follow the instructions found at Microsoft Knowledge Base article 922976.
Enabling AHCI in a system BIOS on installations of Windows XP or Windows Vista will cause SATA Optical drives to disappear. A Hotfix for Windows Vista is available under the title: "SATA optical drives are not available after you start a Windows Vista-based computer."[5] This problem was fixed in Vista SP1.

[geokilla]

Thanks Rooster and Eagle.

My WD 6400AAKS scores. Keep in mind that the drive's been in use for 2 to 3 months already and it has my OS, files, music, games, everything. This is with the AAM set to 254 and all the programs and services that I could think of disabled.