In the Lab
New formfactor offers quiet
performance under loadBuilding BTX
A behind-the-scenes look at Maximum PC testing
I
f you’re the kind of geek who can build
an ATX system in your sleep, you’ll
have to relearn a few things when you
build your first BTX system.
We recently unwrapped a BTX kit to
see just how different it would be to build
a PC using the new formfactor. The kit
wasn’t the traditional tower system we
prefer; instead, it was a slim desktop case
using a microBTX motherboard. Even
so, we figured we’d get our hands dirty
building the machine from the ground up.
Lesson one: Don’t just drop the
motherboard into the chassis and start
screwing it down. BTX requires that you
mount a “support retention module” in
the case. That’s a fancy way of saying “big
metal plate.” The big metal plate is used to
support the honking-big thermal module
BTX cases require. The plates should come
with the case, and the screws you use to
mount it to the motherboard should be
preinstalled in the thermal module.
The retention-plate concept isn’t
completely new to the P4. Intel had a
similar system with its Socket 423 Pentium
4s, but it’s been severely scaled up for BTX
because of the weight it must now support.
Our “BTX-ready” Pentium 4 550 came
in an unmarked white box, but we assume
retail-boxed processors will be about the
same size. This will come as a shock to
anyone who’s ever purchased retail-boxed
CPUs: The new box size is just a little
smaller than a shoebox; the old box is
about the size of a carton of microwave
popcorn.
The good news is that the only major
difference from ATX building is getting used
to the retention plate and thermal module.
After that, the rest is pretty familiar.
We were initially disappointed
with BTX’s obnoxiously loud acoustic
signature, but we can’t necessarily blame
the formfactor. The slim case we built
our system in uses a power supply that
ratchets up to unacceptable levels as theheat increases in the box. Once
we removed the top of the case,
the PSU cooled down and we
were able to see how effective
BTX is. The 3.4GHz P4 Prescott
isn’t exactly an easy CPU to
keep cool and quiet, but even
with CPU Burn In running for a
couple hours, the CPU thermal
module hovered in the 900rpm
range with the case open. The
fan did get loud once in a while,
but it was pretty impressive for
a Prescott system with a 115W
CPU.
Intel expects 2005 to be the
breakout year for BTX; and from
what we’ve seen, the formfactor
has potential. We’ll need to see
it implemented in mid- and
full-tower systems before we can
render a complete verdict, but we
think BTX has a fighting chance.64 MA XIMUMPC MARCH 200 5
This BTX retention plate mounts below the mobo to support the
massive cooling module.Shown side-by-side, we see the old retail P4
kit and the new, double-wide BTX CPU retail
box. The BTX spec uses a gigantic heatsink/fan
assembly that keeps case temperatures low.