Macintel: The Good Is the Enemy of the Best
Daniel Knight - 2005.06.10
The good is the enemy of the best.
Repeat that to yourself as you think about Apple's decision to
adopt Intel's Pentium architecture for June 2007 and later
models.
The good is the enemy of the best.
VHS buried Beta. IBM chose the Intel 8088 CPU over the 8086, the
6809, and the 68000 that was to power the Macintosh. Windows has
perhaps ten times the market of OS X, Linux, and all the other
desktop operating systems combined.
And now Apple is switching from PowerPC processors to Intel
Pentiums.
The good is the enemy of the best.
Today's Intel and AMD CPUs are a far cry from the 8088 and 80286
CPUs used in PC class and AT class computers in the 1980s. They no
longer rely on 64 KB banks of memory, and the 640 KB ceiling of
early PCs hasn't applied in ages. Intel and AMD make some very
powerful CPUs.
But the whole x86 architecture is a throwback to the earliest
days of personal computing, a descendant of the Intel 8080 of the
mid- to late-70s. Each iteration of chip design adds some neat new
features, but each generation also includes full backward
compatibility with the architecture of the past. We're talking 30
years of CPU legacy.
You may remember the snail ads Apple ran explaining how the G3
processor zipped past the Intel Pentium. You may recall the way Mac
websites and PC tech sites shook their head over the Pentium 4 - a
CPU less efficient per clock cycle than the Pentium III that
preceded it.
The older PIII architecture was perhaps one-third more
efficient, but Intel had a hard time pushing the MHz rating forward
- and for the PC user, MHz and GHz means power. It's hard to
explain how a 2.7 GHz G5 can do more work in the same amount of
time vs. a 3.6 GHz Pentium 4. It's counterintuitive.
The best analogy is a very fuel efficient compact car that seats
four vs. a school bus. If you have to transport up to four people,
the miserly subcompact wins hands down. If you need to transport 30
kids to and from a school five miles away, the bus driver only has
to make a single 10 mile round trip. The driver of the car would
have to make 19-20 round trips (three passengers per trip),
depending on whether the car spent the day at school or was driven
back home at the start of the class.
I don't know what kind of mileage a school bus gets, but I don't
think even the most energy efficient hybrids offer twenty times the
fuel efficiency.
The Pentium architecture is more like the fuel efficient car. It
jumps into traffic when the light changes. It zips along very
smoothly. And in most traffic patterns, it will get you to your
destination much more quickly than a bus.
The PowerPC architecture is more like the school bus. It handles
big loads very well.
This is far from a perfect analogy, since both CPUs are fast and
both families of CPUs are getting better (usually more efficient)
with each generation. Apple has AltiVec. Intel has hyperthreading.
AMD has x86 CPUs that are far more efficient than clock speed would
indicate.
The Macintel Future
Intel is already shipping 3.6 GHz CPUs, but the fastest Apple is
shipping is 2.7 GHz. Simple math (3.6/2.7) shows that Intel's
fastest Pentium runs at a 33% higher speed than Apple's top-end G5.
The P4 may be a bit less efficient than the G5, but it would have
to be over 25% less efficient before a 3.6 GHz P4 wouldn't
outperform a 2.7 GHz G5 overall.
There will be areas where one CPU is more efficient than the
other - AltiVec, for instance - but overall the 3.6 GHz P4 will
have no trouble matching or beating the 2.7 GHz G5.
There's always progress, and IBM might be able to deliver 3.2
GHz G5s by the end of the year. (We already know the Xbox 360 will
use a custom 3.2 GHz triple-core IBM Power CPU and be on the market
before the holiday season.) By then Intel may reach the 4 GHz mark,
which will still give the P4 a 25% clock speed advantage over Power
CPUs.
Clock speed isn't everything, but the market sure latches on to
it. Top CPU speeds used to roughly double every 18 months, a
corollary to Moore's Law, but that has slowed since the late 90s.
Intel broke 3 GHz years ago, but 4 GHz is only now
becoming likely. Motorola's G4 architecture tops out at 1.67 GHz,
and IBM's G5 - expected to reach 3 GHz a year ago - still
hasn't attained the 3 GHz mark.
AMD's Athlon 64 and Sempron CPUs, like their Athlon XP
ancestors, are more efficient than Intel's P4s, and AMD indicates
this by by using a performance rating in each chip's name. Thus the
Athlon XP 2800+ runs at 2.25 GHz but provides performance roughly
equal to a 3 GHz P4. AMD's performance ratings tend to be on
the conservative side.
Benefits of AMD's approach include less heat, less power
consumption, and less need for cutting-edge bus speed - the same
kind of benefits the G3 and G4 processors offered in Macs.
Which CPUs in Macintels?
The big question is which Intel CPUs will Apple be using in
future Power Macs, PowerBooks, iMacs, iBooks, eMacs, and minis. As
the personal computing world begins the transition to 64-bit CPUs
(such as the G5), let's hope that Apple has the foresight to put
64-bit Pentiums in the top-end models, at the very least. On the
consumer side, 32-bit CPUs should be good enough for years to
come.
You can almost guarantee that the Macintel models will have
digital rights management built right into the CPU, a feature Intel
has been working on. I suspect Apple will design OS X for
Intel in such a way that it won't run on CPUs that don't have DRM,
just one way of keeping OS X off of standard Windows boxes and
undermining Apple's hardware business.
One factor that I hope Apple will address over the next year is
AltiVec support. Rosetta, Apple's PowerPC emulation layer, doesn't
currently support AltiVec. At the very least, someone should write
a software emulator, but it would be even better if Apple worked
with Intel to build some AltiVec support into the next generation
of Intel CPUs.
One nice thing about the PC world is that there are lots of CPU
choices. Pentium and Celeron from Intel. Athlon 64 and Sempron from
AMD. A few other manufacturers as well. And many times the same
connector is used for a large range of CPUs, making it easy to
upgrade when faster CPUs come to market. I hope that's something
Apple will allow, although they have gone out of their way to make
CPU upgrades a thing of the past on Macs for years now. (Easy CPU
upgrades disappeared with the Power Mac G4.)
How Fast Can Apple Grow?
Right now, Apple is growing 40% year-over-year while using
PowerPC-based hardware. While they may not win the GHz speed wars,
they do win on looks, overall performance, reliability,
functionality, and elegance.
Now imagine Apple offering a dual-core 3.6 GHz Pentium 4 system
that has the looks and elegance of the Power Mac G5. Further
imagine that Microsoft, never one to overlook an opportunity to
sell Windows, ports Virtual PC to OS X on Intel. No more CPU
emulation, so Windows on a Macintel computer should be close to the
performance on a dedicated Windows PC.
Do you see the potential to bring in switchers who won't need to
leave their Windows apps behind? It's huge!
Unless Apple really botches things, Intel-based Macs will have
the same stability OS X users are used to, and clock speed
will be directly comparable with Windows computers. Factor in
Virtual PC, and Apple could quickly rise to 10% market share.
Another benefit of putting OS X on Intel is that Apple could
produce a fully interactive OS X demo that would run from a CD
(or, more likely, DVD) on standard Wintel hardware and lets current
Windows users try OS X without investing in new hardware.
Because Microsoft owns Virtual PC, they shouldn't see any threat
at all from Apple moving to Intel. In fact, because Mac users tend
to buy more software than Windows users, Microsoft may come out
ahead.
More than that, Apple should come out well ahead of where they
are today. I suspect they'll be #2 behind Dell by the time the
entire line has switched to Intel CPUs.
And with the growth, we'll see an even more diverse range of
Macintosh computers. Perhaps an ultralight portable, a quad
processor Power Mac, and a DIY Power Mac for geeks that lets them
choose their own CPU, hard drive, video card, etc.
The good is the enemy of the best, but that doesn't have to be a
bad thing. In the long run, going Intel could be best for Apple and
for Mac users.
