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ATX 12V 2.0
PCI Express graphics cards can suck up to 75 watts of power, compared
with AGP’s 50-watt maximum. ATX 12v 2.01-compliant power supplies
feature a 24-pin connector that jacks into new PCI Express-capable
motherboards. The good news is that you don’t necessarily have to buy a
new PSU to run your new 24-pin mobo. Many motherboards with a 24-pin
connector are keyed to accept an older 20-pin PSU; the extra four pins are
simply left vacant. To make up for the lack of power, some new mother-
boards allow you to supplement the mobo’s main power by plugging in a
second, four-pin connector.Meet the Latest Motherboard Technologies
Should your next motherboard be BTX and support both SLI and DDR2? Don’t be embarrassed if you don’t know
the answer—our CliffsNotes primer on top-end mobo technology will have you spouting geek-speak in less time
than it takes to burn a DVD.DUAL-CORE
CPU SUPPORT
For non-gaming applica-
tions, it’s hard to dispute
the computing performance
you get from two processor
cores housed in a single
CPU. Even if the apps don’t
support it, you’ll still get a
“smoother” experience with
dual cores. AMD says all
Socket 939 motherboards
that can run an FX-55 CPU
will be ready to take dual-
core procs. Yee haw! Things
are a little more confusing
on the Intel side. Intel’s offi-
cial word is that only its new
945/955X chipsets will work
with dual cores, but mobo
vendors we’ve spoken with
say the technology seems
to work just fine with 925X
boards, too. Hmmm. If
you’re shopping for a new
mobo, make sure it supports
dual core.DDR2 RAM
DDR2’s adoption rate has been a slow burn: not as fast as
its cheerleaders predicted, but not as bad as its naysayers
have, umm, nayed. DDR2 improves on DDR by prefetching
twice as much data as DDR, and it’s designed to more than
double the bandwidth of DDR400. DDR2 modules, of course,
are neither physically nor electrically compatible with DDR
slots: DDR2 operates at 1.8 volts, versus DDR’s 2.5 volts, and
has 240 pins compared with DDR’s 184 pins.
Both flavors of DDR2 memory—400- and 533MHz—have
been slightly disappointing thanks to increased latency. But
with DDR2/667 here and DDR2/800 on the horizon, that criti-
cism should subside. We’ll remind you that many people also
pooh-poohed SDRAM, RDRAM, and DDR when they were
new, so we have to ask: Why you gotta player hate?PCI EXPRESS
PCI Express has become a de facto
motherboard standard seemingly over-
night, despite the fact it hasn’t demon-
strated much of a performance boost
over the older AGP standard (at least not
in single-card configurations). PCI-E joins
the trend of moving away from wide,
slow interfaces with lots of pins to nar-
row, high-speed interfaces. It increases
the available bandwidth for graphics
from AGP’s 2GB/s to a whopping 8GB/s.
But PCI-E’s real graphics promise lies
in its upstream bandwidth throughput:
4GB/s compared with AGP’s 133MB/s.
For add-in cards, the standard x1
PCI-E connectors offer about 300MB/s
second of throughput—just about double
that of a standard PCI slot. Considering
the amount of integration on today’s
motherboards, however, few compo-
nents really NeeD to be added. For this
reason, we’ve not yet seen any real ap-
plication for x1 cards; but that’s likely to
change as soon as software developers
create applications that take advantage
of PCI-E.NCQ AND SATA 3Gb
SATA 3Gb is a pretty simple concept:
Take SATA’s maximum transfer rate of
150MB/s, double it to 300MB/s, and
you get SATA 3Gb. Today’s hard drives
don’t need the throughput, but there’s
no reason not to have it on a new
motherboard. Native command queu-
ing is probably more important. NCQ
enables a hard drive and its controller
to intelligently reorder data requests,
so the combo can scoop up and write
data faster. Although we’ve seen only
small performance boosts from NCQ
so far, it’s a good idea to have it on
whatever motherboard you choose.BTX
FORMFACTOR
The BTX motherboard form-
factor moves the processor
to the front of the case, relo-
cates the chipset to deliver
higher I/O speed, and provides
better component cooling. De-
spite these advantages, BTX
has been greeted with about
as much enthusiasm as turd
casserole at a pot-luck. Much
of the resistance springs from
chassis manufacturers, who
are reluctant to spend $50K
to retool their assembly lines.
AMD, meanwhile, has publicly
stated it won’t embrace the
standard unless customers
demand it. We think BTX is
enough of a design improve-
ment that it will eventually
become the new standard, but
you can safely stick with the
older ATX formfactor for the
next 24 to 36 months.MOTHERBOARDS:A-ZMA XIMUMPC MAY 2005