From the
Editor
// ALEXANDER GEORGE //2
KELSEY MCCLELLANdynamically balanced, but
they’re actually randomized in
terms of their BPF [blade pass
frequency],” he says. “So you
don’t get huge harmonics that
tend to be super annoying.” That
means that audible but pleas-
antly pitched fan sounds can be
less noticeable than a measurably
quieter system. The randomiza-
tion technique he’s describing
came from research in car tires.
“There’s a bit of math behind it,
but you can create broadband
noise instead of total noise with
that technique,” he says.
The fans supplement an alu-
minum case, which has two
grids of precision holes, possi-
bly the most ornate examples
of passive cooling ever. Passive
cooling structures absorb heat,
away from vital components,
then dissipate that energy into
the air. The more exposed sur-
face area, the better it works.The Stealth
Cooling
Operation
Inside the
Mac Pro
Hardware
A
S NEITHER A PIXAR
employee nor a You-
Tuber, I don’t need
a Mac Pro. Even the
base model is com-
plete overkill. Spend
a few (tens of ) thou-
sands of dollars on options, and
you can get a 28-core CPU, and
1.5 terabytes of DDR4 memory.
Those numbers imply a level of
engineering I look at from a dis-
tance and say: That’s awesome.
Same as with almost any
product, industry-top perfor-
mance like that creates heat that
needs to be kept away from vital
components. Most high-grade
PCs do this with fans or pump-
driven water systems. But those
can be loud, and if you’ve used a
Mac in the last few years, you’ve
noticed that near-silent opera-
tion is a non-negotiable design
requirement. Which meant that
the Pro’s creators had to find
creative ways to exploit the laws
of thermodynamics.
A team led by Chris Ligten-
berg, Apple engineer and pilot,
handled the fans. “They’re stillNext time you see a motorcy-
cle, look around the engine for
a bunch of thin metal fins. That
busy design creates a lot of sur-
face area for a given volume of
space.
Fins need to stay in one posi-
tion to keep air f lowing through
their channels. But the Pro Dis-
play XDR monitor had to be
able to rotate 90 degrees, which
would have trapped air. So Apple
desinged the holes. “We wanted
free flow through the channels,
no matter the orientation,” says
John Ternus, head of the Pro and
Pro Display’s development. “[The
pattern] gives us a lot of surface
area, which is hugely beneficial.”
Credit Apple’s ubiquity, at
least in part, to that kind of
detail obsession. It’s a controver-
sial company. But however you
feel about its practices or prod-
ucts, few other places would take
temperature regulation this far.CLEAN YOUR
COMPUTER
When dust
blocks airflow,
computers save
themselves from
overheating by
slowing down.
Buy a microfiber
cloth, rubbing
alcohol, and some
compressed
air. Shut down,
unplug, and hit
every opening
you can reach.
Bonus points if
you remove at
least one panel.8 March/April 2020