David Pogue on
the megahertz myth
circuits/nytimes.com
August 30, 2001
From the Desk of David Pogue: Speed Traps
============================
As I noted in a column a few months ago, Apple Computer
has long been the victim of a public perception problem:
that megahertz (MHz) is the true measure of a computer's
speed.
If that were true, Windows PC's would win hands down.
Today, you can buy a PC whose chip runs at 2 gigahertz
(that is, 2,000 megahertz); the fastest Mac runs at 867
MHz. No contest, right? That's what Intel, a key supporter
of the "megahertz-beats-all" myth, would like us to
believe.
As it turns out, megahertz is a bogus measure of
comparative computer speed. First, many other PC
components affect overall speed. But more important, the
megahertz scale differs from chip to chip, so comparing
the MHz of Apple's chips with a Pentium is,
ahem, apples and oranges. Apple's megahertz are "worth
more." As Apple demonstrated onstage at the July Macworld
Expo, an 866-MHZ Macintosh easily blows past a 1.5-
gigahertz Pentium 4.
The perfect analogy to megahertz is the r.p.m., rotations per
minute, of a car engine. This number tells you how fast
the engine turns, but doesn't necessarily correlate to the
speed of a car. (Putting the same engine in both a VW
Beetle and a Mack truck will prove the point.) Still, if
the masses believe that megahertz is everything, how can
Apple compete?
As it turns out, Apple may finally have solved the problem
rather neatly. The new, top-of-the-line Power Mac
computer, which I've been testing this week, has not one,
but two 800-MHz chips inside. It's a great machine -- but
more to the point, it could give Apple the right to
advertise, in other words, that it now has a 1.6-gigahertz
computer.
Now, in the olden days of 1999, having two chips wasn't
much of an advantage. Software must be specifically
rewritten to capitalize on multiple chips, and very few
have been. Microsoft Word 2001 doesn't run any faster on a
dual-chip Mac than on a single-chip machine.
But there's a new element in this equation: Mac OS X.
Apple's new operating system, which comes preinstalled on
every new Mac (but deactivated until you're ready),
automatically capitalizes on multiple processors.
Now, even in Mac OS X, programs must be specially written
to exploit multiple chips -- but that no longer matters,
because Mac OS X itself is multi-chip-savvy. So what if
BeeKeeper Pro can only recognize a single processor? On a
two-chip Mac, BeeKeeper Pro can have one chip all to
itself. The operating system will automatically use the
other one for its own work. Both smart and dumb Mac OS X
programs wind up benefiting from multiple processors.
Of course Apple isn't out of the woods yet. It's still too
soon to say whether consumers will buy the multiple-chip
logic. For that matter, it's still uncertain whether Mac
OS X itself will be a success. And let's not even
contemplate the mess that could result if Motorola gets
out of the PowerPC chip business, as has been rumored.
Even then, though, Apple will always have one last,
desperate ace up its sleeve. Because Mac OS X is,
technically speaking, a layer removed from the chip
itself, Apple could hypothetically write a software
adapter that would let Mac OS X run on chips made by other
companies -- even Intel.
That's a radical, almost ludicrous proposition, one that
would happen only over Steve Jobs's dead body. Apple makes
its money from selling hardware, not software. But if push
ever came to shove, it would be one way for Apple to
escape the shadow of the megahertz myth forever.
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