Barcelona Architecture: AMD on the Counterattack
by Anand Lal Shimpi on March 1, 2007 12:05 AM EST- Posted in
- CPUs
Introduction
Over the past several years, Intel has followed an odd path of microprocessor design. On the heels of the success of the P6 core, Intel set two teams in motion - one to work on the NetBurst architecture that would be the foundation of the Pentium 4, and one to work on a low-cost, low power highly integrated core that would eventually be redesigned into the Pentium M. The team eventually charged with designing the Pentium M took a more evolutionary approach building off of the strengths of the P6 architecture, while the NetBurst team preferred a radical departure from Intel's previously most successful architecture at the time.
We all know how this story ends; as NetBurst evolved, so did the underlying architecture of the Pentium M. Dothan was the first tweak of the Pentium M and it was mostly a clean up job to fix some performance issues with the original core. Higher clock speeds, more cache, and slight increases in IPC were on Dothan's CV.
Intel's Israel Development Center (IDC) then took Dothan and re-architected it to be a native dual core solution, complete with a shared L2 cache, the first of its type for an Intel processor. The Dothan to Yonah progression was far more significant than the move from Banias to Dothan, not just because Yonah was dual core but also because of the many architectural improvements that went into Yonah.
The next step Intel took is one we're all familiar with, and involves the most radical design change of the Pentium M's short lived history; Intel took Yonah and made it wider, deeper, and far more efficient. Out came the Core 2 line of processors and with it, Intel regained the undisputed performance crown it hadn't seen ever since the debut of AMD's Athlon 64.
While many argued that Banias, the first Pentium M core, was merely a modern take on the P6 architecture it's hard to see much in common between today's Core 2 and the 11 year old Pentium Pro. The P6 core was a starting point for a long line of evolution that brought Intel to where it is today.
AMD took a far more conservative approach over the past several years; it all started with the success of the K7 core, effectively a wider, faster, competitor to later versions of Intel's P6 architecture. While one of Intel's teams was busy making radical departures from anything AMD or Intel had done in the past, AMD didn't have the luxury of running two large scale microprocessor projects in tandem. The solution was to take the K7 core and improve on it, rather than taking a risky step in a different direction.
The K8 core was born as an evolution of the K7; with a slightly deeper pipeline, slight architectural improvements and an integrated Northbridge, the K8 was a pretty major evolutionary step for AMD over the K7. In fact, it took the Core 2 Duo to truly outperform the K8 core across the board, although Dothan and Yonah came quite close in certain applications.
AMD had worked on dramatic successors to the K8, rumored to be K9 and K10, but both appeared to be scrapped or at least focus was shifted away from them in favor of a more evolutionary take on the K8 architecture. The main difference here that allowed Intel to catch up to AMD's performance is that while Intel's Pentium 4 team was operating on the usual schedule of a 5-year micro-architecture cycle, the Pentium M team at IDC was updating its architecture every year. Banias, Dothan, Yonah and Merom/Conroe all happened in a period of four years, and during that same time AMD's K8 remained unchanged.
If Intel had continued down the Pentium 4/NetBurst route, sticking to the usual 5-year design cycle would have probably worked just fine for AMD but Intel had the luxury of having two major micro-processor teams working in parallel, one of which had a much better idea. Luckily it would seem that AMD realized it needed to compete with Intel using smaller evolutionary steps every couple of years rather than leaving an architecture relatively untouched for 4 - 5 years and thus the Barcelona project was created. Although it's set to debut around a year after Intel's Core 2 Duo that swiped the performance crown, Barcelona is AMD's best chance at remaining competitive.
Barcelona's window of opportunity is slim, depending mostly on how Intel's transition to 45nm goes. Publicly Intel has stated that its architectural update to Core 2, codenamed Penryn, will begin shipping by the end of 2007. However, current roadmaps show availability at sometime in 2008 with no word on when significant quantities will be available. Should Intel take longer than expected with the move to its 45nm Penryn core, Barcelona's mid-2007 launch on servers and Q3 '07 launch for desktops may come at a relatively quiet time for Intel.
Over the past several years, Intel has followed an odd path of microprocessor design. On the heels of the success of the P6 core, Intel set two teams in motion - one to work on the NetBurst architecture that would be the foundation of the Pentium 4, and one to work on a low-cost, low power highly integrated core that would eventually be redesigned into the Pentium M. The team eventually charged with designing the Pentium M took a more evolutionary approach building off of the strengths of the P6 architecture, while the NetBurst team preferred a radical departure from Intel's previously most successful architecture at the time.
We all know how this story ends; as NetBurst evolved, so did the underlying architecture of the Pentium M. Dothan was the first tweak of the Pentium M and it was mostly a clean up job to fix some performance issues with the original core. Higher clock speeds, more cache, and slight increases in IPC were on Dothan's CV.
Intel's Israel Development Center (IDC) then took Dothan and re-architected it to be a native dual core solution, complete with a shared L2 cache, the first of its type for an Intel processor. The Dothan to Yonah progression was far more significant than the move from Banias to Dothan, not just because Yonah was dual core but also because of the many architectural improvements that went into Yonah.
The next step Intel took is one we're all familiar with, and involves the most radical design change of the Pentium M's short lived history; Intel took Yonah and made it wider, deeper, and far more efficient. Out came the Core 2 line of processors and with it, Intel regained the undisputed performance crown it hadn't seen ever since the debut of AMD's Athlon 64.
While many argued that Banias, the first Pentium M core, was merely a modern take on the P6 architecture it's hard to see much in common between today's Core 2 and the 11 year old Pentium Pro. The P6 core was a starting point for a long line of evolution that brought Intel to where it is today.
AMD took a far more conservative approach over the past several years; it all started with the success of the K7 core, effectively a wider, faster, competitor to later versions of Intel's P6 architecture. While one of Intel's teams was busy making radical departures from anything AMD or Intel had done in the past, AMD didn't have the luxury of running two large scale microprocessor projects in tandem. The solution was to take the K7 core and improve on it, rather than taking a risky step in a different direction.
The K8 core was born as an evolution of the K7; with a slightly deeper pipeline, slight architectural improvements and an integrated Northbridge, the K8 was a pretty major evolutionary step for AMD over the K7. In fact, it took the Core 2 Duo to truly outperform the K8 core across the board, although Dothan and Yonah came quite close in certain applications.
AMD had worked on dramatic successors to the K8, rumored to be K9 and K10, but both appeared to be scrapped or at least focus was shifted away from them in favor of a more evolutionary take on the K8 architecture. The main difference here that allowed Intel to catch up to AMD's performance is that while Intel's Pentium 4 team was operating on the usual schedule of a 5-year micro-architecture cycle, the Pentium M team at IDC was updating its architecture every year. Banias, Dothan, Yonah and Merom/Conroe all happened in a period of four years, and during that same time AMD's K8 remained unchanged.
If Intel had continued down the Pentium 4/NetBurst route, sticking to the usual 5-year design cycle would have probably worked just fine for AMD but Intel had the luxury of having two major micro-processor teams working in parallel, one of which had a much better idea. Luckily it would seem that AMD realized it needed to compete with Intel using smaller evolutionary steps every couple of years rather than leaving an architecture relatively untouched for 4 - 5 years and thus the Barcelona project was created. Although it's set to debut around a year after Intel's Core 2 Duo that swiped the performance crown, Barcelona is AMD's best chance at remaining competitive.
Barcelona's window of opportunity is slim, depending mostly on how Intel's transition to 45nm goes. Publicly Intel has stated that its architectural update to Core 2, codenamed Penryn, will begin shipping by the end of 2007. However, current roadmaps show availability at sometime in 2008 with no word on when significant quantities will be available. Should Intel take longer than expected with the move to its 45nm Penryn core, Barcelona's mid-2007 launch on servers and Q3 '07 launch for desktops may come at a relatively quiet time for Intel.
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agaelebe - Friday, March 2, 2007 - link
Wow! A lot of dicussion in here.And, by the way, very interesting article.
I'm a software engineer from Brazil and I'm planning to change my PC this year.
I've bem using AMD processors since the K6.
Today I've a XP Mobile 2500+(@2.2ghz), 1gb ram, 200gb and an AGP 6600GT
My PC is not very slow, but I'm thinking in going dual core to speed things up(office applications, web development and some games).
I can run some of the newest games, but not in high graphics.
I expect that my PC can run C&C 3 (Already run the demo in 1024 medium, but have some craches although it's not running it slow)
So, today I'm thinking in 3 options:
1) Stay with this computer and wait until AMD launchs it's new architecture (I pretend to go with an average price Kuma)
2) Go with Intel Core 2 Duo (e6300 or e6400). They're not expensive and for games I can easily make an overclock and gain more performance.
3) Buy a good AM2 board and a cheap Atlhon X2 (3600) and wait new AMD processors and then change only the processor.
Here in Brazil the taxes are to high, so I'm planning in buying a PC with these specs:
- CORE 2 Duo e6300/6400 or X2 3600/3800
- mid-tier motherboard (
- 2 x 1gb DDR 800 4-4-4-12
- 2 x 250 gb
- X1950pro 256 or 512
- 500watts power
So the prices are below:
e6300 box US$ 300 (same price for a X2 4200+ box)
x23800 box US$ 220
motherboard: US$ 220
ram: US$ 400
video: US$ 450
DVD: US$ 70
case: US$ 150
HDs : US$ 250
Power: us$ 180
So I plan to spent about 2000 dollars (Sadly, I can buy this same PC in US for the half of the price).
My new PC should spent not to much power so I can leave it turned onall day long(max 150watts on iddle without monitor), otherwise I'll keep my old computer turned on just for downloding stuff)
So, If someone has an opinion, I'd like to "hear" it. You can give another options to, or make some comments about the specs I'm choosing now.
I had Pentium 75 and after that only AMD CPUs... Should know I surrender to the Core 2 Duo or believe that AMD can really beat it until the end of 2008?
And thanks for the cooperation and patience.
Zebo - Saturday, March 3, 2007 - link
Athlon 64 AM2's arnt exactly slow so if you're an AMD fan just get one..like a 3800+ or 3600+ and overclock it. It will be at least 4x faster than what you have now and accept K8L Agena core later. It will be cheaper than C2D by about $50 USD and You'll also pay cheap for a GeForce 6100 Motherboard which is only $50 USD. Overall expect the the AM2 system to be about $100 USD cheaper.Keep in mind that C2D is 20% faster clock for clock in most apps so it's not exactly a quantum leap here getting a C2D.. Gap gets a lot larger when overclocking since C2D's overclcok higher like 3.2Ghz is common on air vs. only 2.8Ghz for AM2, so, at the end of the day a C2D setup is able to be about 40% faster over most benchmarks. That is getting significant and why enthusiasts are buying C2D's.
agaelebe - Friday, March 2, 2007 - link
And,as always, sorry with the errors and not so good writing...Kiijibari - Thursday, March 1, 2007 - link
Hi,never heard of of that before, does anybody know what it is ?
So far I see 2 pad areas at the DIE photo, therefore I assume that it would be also 2 interfaces, e.g. x8 PCIe like Sun uses ?
bb
Kiijibari
mino - Friday, March 2, 2007 - link
It should be some management/coodrination stuff (can-t remember the name of that bus).Every northbridge and CPU has that.
davecason - Thursday, March 1, 2007 - link
Anand,Great article! I know it took a lot of time and I wanted you to know I really appreciate your effort. It is the kind of article that keeps me coming back to your site.
-Dave
yyrkoon - Thursday, March 1, 2007 - link
Page 5, paragraph 4 'pretty significantly'. Well is it, or is it not it ?
http://www.wikihow.com/Avoid-Colloquial-%28Informa...">http://www.wikihow.com/Avoid-Colloquial-%28Informa...
Aside from my gripe concerning writing style, good article :)
trisweb2 - Friday, March 16, 2007 - link
Usually we criticize writing style based on a whole experience... obviously Anand is one of the best technical review writers on the Internet; if you bother to read his articles more fully perhaps you'd realize that. The colloquial writing sometimes brings it to a more personal level that a reader can better relate to and understand -- it works especially well in this case, where it's a future design, we really don't know how it's going to perform. That he can guess and say "pretty significantly" tells me he understands the uncertainty of the situation, and the language communicates that fact perfectly well. It would be more confusing if he said it would impact performance "significantly" as you want him to, as that would imply that he was more certain than he might actually have been.Masters are allowed to bend the rules, and Anand is one, so lay off.
yyrkoon - Thursday, March 1, 2007 - link
*Is it, or is it not*/me hangs head in shame
baronzemo78 - Thursday, March 1, 2007 - link
Any rough guess as to how Barcelona will compete with Core2 in gaming? Many articles have shown how Core2 gets you a slight FPS boost in games that aren't graphics card limited. I'm curious how Barcelona will fit in with the overall picture of DX10 cards like G80 and R600.