64 | MAXIMUMPC | NOV 08 | http://www.maximumpc.com
Odds and Ends
Before you POST your new system to install the OS, you should disable
unneeded ports and make your decision to run either AHCI or IDE
When we build a new system, one of the first things we do is flip
through the BIOS, turning off things we know we won’t ever use,
such as the serial port and parallel port. If your system doesn’t
include a floppy drive (some still do), we also flip off the floppy
controller in the BIOS. Turning these features off saves some system
resources, but it mostly just makes us feel good.
If you dig into your BIOS you’ll also see a setting that lets you
configure your SATA ports as IDE, RAID, or AHCI. Default shouldbe IDE and most people understand that setting RAID turns on the
RAID features of the chipset, but just what is AHCI? It’s the Intel
specification dubbed Advanced Host Controller Interface that
enables such fancy features as native command queuing and hot-
plugging of SATA devices. If you leave AHCI off, your drives will
run in an emulated IDE mode. The rub is that AHCI is not supported
in Windows XP natively. You will have to use a floppy drive and F6
drivers or create a slipstreamed version of XP with AHCI drivers just
to install the OS. If you already have Windows XP installed, flipping
on AHCI will prevent the OS from loading. It’s also not clear what
level of AHCI support Vista has, but if you install with AHCI on, you
don’t need to install drivers. If you install Vista in IDE mode, how-
ever, and then turn on AHCI mode in the BIOS, the OS bluescreens.
Do NCQ and hot-plugging make AHCI worthwhile? For the most
part, no. NCQ can actually hurt performance in some situations.
Still, there have been online reports of chipsets performing quite
poorly unless AHCI is enabled. AHCI is supported only by Intel and
ATI at this point and not by Nvidia.The BIOS is older than many of the people who actually use a
PC, so why in this age of 3D-accelerated 64-bit operating sys-
tems are we still using a line-based interface and 16-bit real-
mode BIOS? That’s a conundrum the industry is hoping to fi x
with the Unifi ed Extensible Firmware Interface, which may well
replace many of the things the BIOS does today. An obvious
advantage of UEFI is that it supports a GUI and mouse controls.
UEFI would also be processor agnostic, use higher-level lan-
guages such as C++ instead of assembly language, and pretty
much make booting your PC more like, well, booting a Mac.It won’t happen overnight, though. Few desktop mother-
board vendors beyond MSI have hopped onto UEFI and only
the 64-bit fl avor of Windows Vista SP1 supports it. Even if
UEFI takes off, the BIOS will not totally go away. It’ll just get
a serious demotion to doing very basic power on self-tests
before handing over control to UEFI. The difference is that you
may access those familiar controls using a UEFI GUI interface,
which will also roll in pre-OS applications as well.A NEW WAYUEFI Promises to Make
BIOS Tweaks More User
Friendly
Turning on AHCI mode will require installing drivers via F6 with
Windows XP.MSI has already made UEFI available on a limited set of motherboards.OLD TECH, NEW TWEAKS