MaximumPC 2005 06

48 MA XIMUMPC JUNE 2005

pretty much SOL. Despite conflicting

hearsay from motherboard makers (and

from Intel itself), the final word is that

you’ll need a dual-core capable chipset

to run the new chips—even though the

dual-cores are Socket 775 processors.

We’re rather concerned about the con-

fusion within Intel, but the company tells

us a lack of dual-core support is an inher-

ent limitation within the 915/925X/925XE

chipset family. That’s pretty dumb when

you consider that the 925XE chipset is

practically brand-new. So, if you just

bought an Intel board, in the immortal

words of Handy Andy: “It sucks for you!”

Q

Which operating systems will

support dual-core chips?

A

Without proper operating-

system support, multiple-CPU

systems will show up as single-

CPU systems. Microsoft has

committed to licensing Windows based

on the number of CPU packages, not on

the number of cores, so you’re good to go

even if you’re running Windows XP Home

Edition (which supports only single-

processor systems). Numerous Linux

distributions already support multiple

processors via special SMP (symmetric

multiprocessing) versions of the kernel.

Q

So, with single-core procs hit-

ting a practical ceiling in terms

of heat and power consump-

tion, the emphasis on future

designs will be to add more cores?

A

Roger that. Intel predicts that

by 2008, consumer-level CPUs

will be able to handle eight

threads simultaneously. Those

cores will probably include Hyper-

Threading, but that still means you

should expect to see quad-core CPUs in

just a few years. Besides adding more

cores, you can also expect AMD and

Intel to continue to add cache, increase

clock speeds, add special instructions,

and build entirely new architectures to

further accelerate performance.

Once applications are recompiled to

fully utilize multi-core CPUs, consumers

can expect to see phenomenal perfor-

mance gains that will handily eclipse

any boost you’d get from 200MHz speed

jumps or beefier cache sizes. If an ap-

plication can scale perfectly with the

additional cores, it’s conceivable that the

time it takes to encode a video could go

from, say, 100 minutes with a single-core

CPU, down to 50 minutes with a dual-

core CPU, and plummet even further

to 25 minutes with a four-core proces-

sor. You may not experience the same

dramatic speed jumps across all your

applications, but there’s no doubt that

adding cores will increase performance

for any applications that support them.

Q

Tom Halfhill’s “Fast Forward”

column last month discussed

multi-chip processors. Is that

different from multi-core or

dual-core procs?

A

Yes. Multi-chip refers to more

than one chip in a CPU. With

its 90nm dual cores, Intel hunts

through its wafers for cores

that don’t have glitches and that can hit

the clock speeds it needs. But because

the slice of silicon—i.e., the die—that

both CPU cores reside on is now much

larger, the yield of good CPUs per wafer

goes down. With the 65nm version of

the CPU, Intel says it will have a sys-

tem where it will no longer need two

actual cores on a single die. Instead, the

company will pick out single cores and

bond them into the same CPU package

to create a multi-chip processor. That

should drastically increase the yield per

wafer. Intel says, while it makes sense

for the next-gen version of the Pentium D

(code-named Presler), that doesn’t mean

it will always be that way. Are these true

multi-cores? Not really, says analyst

Kevin Krewell; “they sorta cheated.”

Q

When will I be able to buy a

dual-core system?

A

Those of you accustomed to the

avalanche of processors that

often follow product launches

may be disappointed by the

more modest rollout AMD and Intel

have planned for dual core. Instead of a

bombardment, expect the wares from

both companies to trickle out. Intel’s

dual-core Pentiums will debut in mod-

est numbers early this summer, while

AMD’s dual-core Athlon 64s will hit in

June. AMD says it expects elite system

vendors to have the dual cores first, with

the parts turning up in volume within

a month of launch. Prices haven’t been

publicly announced, but you can expect

the Pentium D to tip in at around $500;

the Extreme Edition will likely cost twice

that much. AMD’s pricing is anyone’s

guess at the moment.

As you can see on the right,

playing Quake III on our dual-core

P4 system barely registered on

the CPU Usage graph.