by February 22, 2006 0 comments

Dual core processors have suddenly exploded upon us. We
were nicely chugging along, totally content with our 64FX processors when
suddenly poof! AMD hit us with their X2s and Inte with their Pentium Ds. The
battle for dual core supremacy has continued on and now Intel has launched Yonah,
or Core Duo/Solo as it chooses to call it.

We have long wondered what each processor would do in real
world tests and what kind of real, tangible performance gain we can expect from
them. When we got our hands on a couple of Yonah powered notebooks, we felt this
was the right time to compare the top notch performances of these processors and
figure out which one is better and from past experience, where Intel has reached
in terms of performance Vis-à-vis AMD.


X2 4800+: NA; X2 4200+: Rs 29,200 Pentium D 840: 
Rs 29,700; ASUS W5F (Yonah Notebook): Rs. 1.1 to 1.2 Lacs
High performance PCs and notebooks 
See comparison table
Pros: X2 4800+: Fastest processor around, dual-core; X2 4200+: Fast performance, affordable; Pentium D 840: Dual-core, execute disable, excellent price; Intel Core Duo T2500: Dual-core, ultra low power consumption, extreme performance
Cons: X2 4800+: Too expensive; X2 4200+: Only 512KB L2 cache/core; Pentium D 840: High heat generation; T2500: Not backwards compatible with earlier socket 479 boards
Contact: IT Solutions, New DelhiTel: 26818501 
For X2: RQS# E11 or SMS 131102 to 9811800601
For Pentium D: RQS# E12 or SMS 131202 to 9811800601
For Yonah: RQS# E31 or SMS 133102 to 9811800601

The processors used were AMD’s Athlon X2 4800+, 4200+,
Intel’s Pentium D 840 and the W5F, a Core Duo T2500 based notebook from ASUS.

What’s Yonah
To re-iterate, Yonah is Intel’s dual core offering for the mobile
platform. Yonah is really the codename. The marketing name is Core Duo or Core
Solo depending on whether it is dual core or single. It is based on a whole new
fabrication process, it is thinner than the earlier processors, faster than the
Pentium M and uses far lesser power to go about its business. If this was not
enough, its light as air and if you were to hold one in your hand, you would
think it was a silicon dummy.

The promises that Intel has made with Yonah are quite
serious. The most important claim being that it can run two cores at the same
power consumption levels. So you get twice the performance while your battery
life at least stays the same if it is not indeed enhanced.

The Yonah core that forms Intel’s dual core strategy. This is also called the CoreDuo

The processor still is a 479 pin variety however, this in
no way means that you can take a 479 pin board from your old Pentium 4s and
stick the Yonah in it. No way. Even though the processor uses 479 pins, Intel
has changed the pin configuration so no backward compatibility. If you just
invested in a new notebook with the Pentium M, hard luck.

The main reason for the unbelievable size of the processor
is that unlike the Pentium D (which is rather huge) it is based on the 65nm fab
process and each core accesses a shared cache. In Pentium D, the 2MB cache is
basically divided between the two processors so that each has access to a full

With the Yonah, Intel has once again changed the
nomenclature of its processors. The three digit numbers are now gone and they
have been replaced by an alphabet followed by 4 digits depicting the expected
performance level of the processor. There is no necessity however that a
processor with the tag of T2500 is running at 2.5 GHz. The names are perhaps
indicative of the expected performance levels or classification of the
processors. If this were so Intel would’ve done something rather ironic. It
would’ve copied AMD’s nomenclature concept. Funny thing being that AMD’s
names were based on Intel in the first place!

Anyway, the T followed by a 2xxx means that the processor
is dual core. A T followed 1xxx implies a singe core or Core Solo processor. All
the Txxxx processors consume only 31W of power and have all the goodies such as
EIST and Execute Disable.

The fact that they use such a small amount of power in no
way means there are no ULVs. The ULV dual core range currently consists of the
L2400 and L2300, both of which utilize a mere 15W of power and run at 1.66 and
1.5GHz respectively.

The key specs of the Athlon X2. Virtualization technology will make its way into the CPU in the coming year

Yonah is the result of some rather splendid engineering by
Intel guys over in Israel. They have at once, managed to retain some of the best
features and learnings from processors gone by (both desktop and mobile). They
have also managed to iron out some of the issues plaguing the current generation
of processors. All this has led to rather incredible performance gains both in
speed as well as power maximization.

The Instruction Pipeline
The first thing that changed quite dramatically is the instruction pipeline.
It is down to around 12 from the mega 30+ in the Pentium 4s. Think of a pipeline
as an assembly line.

To give you a small example, imagine there are 10 people
assembling a PC on the assembly line. Each guy is doing one part of the job.
There is one guy attaching the hard drive, another attaching the RAM, third,
screwing the cabinet together and so on. Obviously, since each person is doing
just one job, he will need much lesser time and the PC will move from one stage
to the next pretty fast. However, you will need a lot of people to finish the
PC, which will make your assembly line rather long. This is akin to a long
instruction pipeline, which results in a higher clock speed.

On the other hand, if you make each person do multiple
jobs, it will reduce the overall assembly line’s length but each stage will
obviously take longer. This is equivalent to a shorter pipeline, which results
in a lower clock speed.

The fact is that the 65nm fabrication coupled with a
shorter pipeline ensures lesser power consumption and overall heat dissipation
which does give Intel a bit of a head-room to crank up the clock speeds of the
processor. We think that even though right now, the Core Duo processors start at
a mere 1.66 GHz and go up to only 2.16 GHz, we would not be surprised if there
are more Core Duos launched with speeds up to 2.4 GHz /core.

Smart Cache
This is another indication of why Intel’s Pentium D has been languishing
behind AMD’s X2 for so long. Intel didn’t realize that just putting in two
cores into a processor will not help performance all that much. What is equally
important is the way the two cores interact. So far, the way Pentium D was doing
this was rather silly.

In AMD’s X2, there is a system, which ensures that the
cores keep accessing the common cache and are able to interact with each other
at core speeds. This ensures that precious clock cycles are not wasted while the
system waits for the painfully slow bus to do the needful.

In Pentium D, if core 1 wants to talk to core 2, the
message is taken out of the core using a painfully slow bus, and then finally
enters the other core where it is processed and sent back. All this while, core
1 is obviously waiting for the message to come back because it has obviously
kept things on hold (out of order execution capabilities not withstanding).

ASUS W5F, Core Duo
makes a debut

Intel has only just launched its Core Duo processors (code named Yonah).
The claim being made is that you get a dual core processor, essentially
twice the performance, and at least the same battery life. Well, we hardly
take any one’s word for these things and decided to test it out
ourselves. The results were stunning. Our version of the W5F came pre
loaded with Win XP Pro SP2; the Core Duo T2500 2.0 GHz per core and 1 GB
of RAM. We ran the full spec benchmark on this machine. We haven’t
compared it to other notebooks because the W5F performs more like a
desktop beast than a thin, light and portable notebook.

The form factor is
quite portable. The 12.1 inch screen is sharp and gives you a near 180
degree viewing angle. It comes with a built-in 1.3 megapixel camera that
swivels, placed at the usual lid latch spot. This means that your
notebooks lid never locks into place and is always hanging open for all
practical purposes.

The battery took almost
an hour and forty minutes to charge up. Our BatteryMark test with full
screen brightness and disabled power management gave it a full 3 hours on
batteries! In the SysMark 2004 Internet Content Creation (ICC) the
notebook scored very a high score of 226. Sadly, our sample was using
Intel’s integrated graphics which meant we couldn’t really give it a
true graphics performance whirl. In our raw power tests like compression
and Super Pi this processor came second only to the Athlon X2 4800+ and
that really says it all about the potential here.

At Rs 1,20,000, this
notebook is an excellent blend of performance, battery life and
portability. Still, it does lack that sense of style and panache.

In Yonah, Intel has fixed this problem and has done a
brilliant job at that. Yonah does away with the entire concept of different
caches for each processor. It just pools in all the cache and connects both
processors to it with a bus. The bus then works somewhat like the on-die memory
controller found on the AMDs and ensures that the cores can talk to each other
at much faster speeds than before.

Obviously, this still does not mean that the Yonah cores
can communicate at core speeds and to be fair, AMD’s on die controller is
still a master solution to this problem as it does away with the need for a BUS
for all practical purposes.

Now you might ask why the two cores would want to
communicate to each other in the first place? The reason is quite simple. Just
because there are two cores doesn’t mean they are doing things independently
and are processing completely different streams all the time. There will be
times when they will need to work on the same data. This means that each core
needs to know the most current data storage location/processing status so it can
work on the correct data set.

Another interesting thing is that the cache allocation to
each core is dynamic. In fact, if there is very little requirement for cache,
the memory controller will flush out everything stored in the cache to the main
memory and put the cache in the off stage. This again helps in power saving but
ensures that the cache latencies are higher, indeed, in Yonah, the L2 cache
latency is as high as 40% more than what we have seen on Dothan (Pentium M).

Intel’s Digital Media Boost
Intel was the pioneer of bringing multimedia home when it started with the
MMX and multimedia technologies back in the days of Pentium and Pentium II etc.
Even though multimedia capabilities of the processors have increased many folds
on the desktop, their mobile counterparts have suffered in this area. The prime
reason has been that such applications require enhanced SIMD (single instruction
multiple data) operations as well as multi thread processing at the instruction
level. This obviously sacrifices power savings and has not been so far
incorporated into a processor.

This has however changed with Intel giving Yonah completely
media oriented capabilities. All of Yonah’s decoders will support SSE3
instruction decoding, where SSE3 is the 3rd generation of Single SIMD
Extensions. The first was obviously MMX and the second being SSE2 which was seen
on the Pentium IIIs.

All this will ensure that if you were to use your notebook
for heavy multimedia use like graphics editing and perhaps even 3D modeling (by
extension gaming? We hope so!), it would give you much better performance than
you would otherwise get on a notebook. Again, all this while your notebook’s
battery life stays the same!

Dual Processor Shootout
Tests Test Done X2 4800+ Pentium D 840 X2 4200+ T2500
System Benchmarks
Sysmark 2004          
Sysmark 2004 Rating   222 199 211 206
Internet Content Creation Overall 293 247 272 233
  3D Creation 271 225 264 226
  2D Creation 340 286 323 274
  Web Publication 274 234 236 204
Office Productivity1
  Overall 183 160 168 163
  Communication 150 117 148 146
  Document Creation 220 183 219 215
  Data Analysis 187 193 145 138
BW 2004  Default settings 32 31 22.7 21.6
Super Pi (No. of Seconds) 2M digits of Pi 80.21 sec 98.76 84.63 75.27
Gaming (Max Settings)
Doom3 1600×1200 49.8 43.6 44.6 NR
F.E.A.R 1280×960 36 31 33 NR
Far Cry 1600×1200 111.52 103.65 100.35 NR
Video Compression VOB to XVID 136s 135s 1374 135
WinRaR 526MB To 262MB 169.64 195.61 175.65 173.25

Napa V/S Sonoma
The earlier mobile platform was codenamed Sonoma. This was the platform that
was used in the Pentium Ms (Dothan) that we all use today. Napa is the newest
mobile platform from Intel. It is based on the Yonah processor and the 945
mobile chipset. It promises to upgrade the overall speed as well as power
consumption optimization of the entire platform.

The reason why we need to understand the platform
specifications is simply because Intel itself has moved away from providing
processor centric solutions to providing entire platforms that make everyone’s
lives a little easier. In Napa, for the first time, the FSB is clocked higher
from the 533 MHz of Sonoma to a cool 667 MHz. We suspect that if Intel really
wanted, it could’ve given us a much higher clocked FSB but that obviously
would’ve translated into more power consumption, something Intel is not too
keen on right now.

The Test Setup
The notebook ASUS sent us consisted of 1 GB of RAM, a 40 GB hard disk drive
and of course the Core Duo T2500 processor. This is the second fastest processor
in the Core Duo stable. To compete with it, we lined up the X2 4800+, the X2
4200+ and the Pentium D 840.

The test bed used was an ASUS A8N-SLI, 1 GB DDR400 RAM,
7200rpm SATA HDD and NVIDIA 7800GT graphics.

We benchmarked the processors on a variety of tests, from
office productivity to raw power and rest assured the results were nothing short
of stunning!

How they fared
We started with an overall system benchmark using SysMark 2004. As expected,
the X2 4800+ zipped ahead of everyone with a score of 222 but guess what the
T2500 scored, a cool 206! Just 16 points short of a 4800+ is perhaps a statement
in itself. When you think about the fact that this score was achieved on a
notebook with a slower HDD, it becomes even more impressive.

In almost all the other tests, the T2500 was nowhere near
the Athlon X2, which was the fastest processor in every test except two (more on
this later). What we did find very intriguing was the fact that Yonah
outperformed the Pentium D 840 quite considerably in most tests. This in itself
is testament to the Smart Cache and Media Boost technology implementations that
Yonah enjoys.

We also did some hardware independent purely processing
tests like Super Pi and WinRAR compression. In Super-Pi, we were simply stunned
to see that the T2500 actually outperformed the X2 4800+ by a good 5 seconds! We
were so surprised by this that we ran this test twice just to be sure!

In WinRAR, the X2 with its higher core clock did manage to
outdo the T2500, which came in second, leaving the X2 4200+ and the Pentium D to
bring up the rear. To ensure that we are using a practical dataset, our 526 MB
of data consisted of ppts, TIFFs, word files, excel files, outlook express
folders and so on.

We were unable to run the gaming benchmarks on this
notebook because sadly, even now, Intel’s IGP is practically good for nothing.
We are just waiting for an Xpress600 or an NVIDIA C51 based board to come along
for Yonah so we can have workable onboard graphics. However, we suspect that
Yonah, without an on-die memory controller would’ve certainly lost out to the
AMD processors.

Bottom line: To sum up, if you read our previous article on
Intel’s nomenclature and took our advice to hold on before buying a notebook,
you did well by listening to us. Yonah, or Core Duo, is one of the best mobile
processors we have ever come across. The mere fact that it can give X2s a run
for their money while giving you atleast the same battery life as a Pentium M is
truly commendable. Take a bow Intel, excellent job!

Varun Dubey

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