Barcelona Architecture: AMD on the Counterattack
by Anand Lal Shimpi on March 1, 2007 12:05 AM EST- Posted in
- CPUs
Final Words
When Intel launched its first Core 2 based microprocessors, the performance improvement was beyond revolutionary. It was the biggest single performance improvement we had seen from a new microprocessor in several years at that point. A large part of Core 2's success was its architecture, but you cannot ignore that it couldn't have come at a better time for Intel.
All Conroe, Merom and Woodcrest had to do was outperform Intel's aging and misguided NetBurst based Pentium 4 processors. Doing so proved quite easy for AMD, which had been doing just that pretty much since the 2000 launch of the processors. With no competition from within Intel, AMD wasn't really doing that much better. While the K8 was a strong architecture, it was getting old. Without any serious performance enhancing architectural updates since its introduction back in 2003, AMD left Intel with a stationary target to aim for. With each successive iteration of the Pentium M architecture, Intel came closer and closer to developing its own Athlon 64 killer, eventually culminating in the release of such a product - the Core 2 Duo.
It wasn't some mystical force of microprocessor design prowess that allowed Intel to pull ahead last year; it was a good architecture and excellent timing. Ironically enough, it was the same two elements that orchestrated much of the success of AMD's K7 and K8 architectures; they were both good designs released at times when the competition was at its worst.
In terms of actual product releases, the first incarnation of AMD's new architecture will be found in the next-generation Opteron due out at the middle of this year. AMD will initially launch at speeds ranging from 2.1GHz to 2.3GHz, but by the end of this year you can expect higher clock speeds. On the desktop, AMD's Agena core will be a Barcelona equivalent shipping at between 2.7 - 2.9GHz. Kuma will be a dual-core variant of Agena shipping in the 2.0 - 2.9GHz range.
Barcelona will be a success for AMD; the long awaited architectural update to K8 should yield significant performance improvements, especially in current areas of weakness for the K8 (e.g. video encoding). Our review of the Athlon 64 X2 6000+ showed that with aggressive pricing, AMD could come close to offering something competitive to Intel. At current prices, we suspect that Barcelona would be enough to close the gap between AMD and Intel. Chances are that we won't see bargain basement prices on AMD's new cores, but we'd expect that AMD would have to maintain a competitive market.
The real catch here is what happens after Barcelona; as we mentioned before, Intel's current successes were born out of steady but regular evolution of a good starting architecture. With yearly updates to the Pentium M, Intel achieved a snowball effect that proved difficult to stop. It would seem that a similar approach by AMD would be necessary to avoid sticky situations like the one it finds itself in today.
When Intel launched its first Core 2 based microprocessors, the performance improvement was beyond revolutionary. It was the biggest single performance improvement we had seen from a new microprocessor in several years at that point. A large part of Core 2's success was its architecture, but you cannot ignore that it couldn't have come at a better time for Intel.
All Conroe, Merom and Woodcrest had to do was outperform Intel's aging and misguided NetBurst based Pentium 4 processors. Doing so proved quite easy for AMD, which had been doing just that pretty much since the 2000 launch of the processors. With no competition from within Intel, AMD wasn't really doing that much better. While the K8 was a strong architecture, it was getting old. Without any serious performance enhancing architectural updates since its introduction back in 2003, AMD left Intel with a stationary target to aim for. With each successive iteration of the Pentium M architecture, Intel came closer and closer to developing its own Athlon 64 killer, eventually culminating in the release of such a product - the Core 2 Duo.
It wasn't some mystical force of microprocessor design prowess that allowed Intel to pull ahead last year; it was a good architecture and excellent timing. Ironically enough, it was the same two elements that orchestrated much of the success of AMD's K7 and K8 architectures; they were both good designs released at times when the competition was at its worst.
In terms of actual product releases, the first incarnation of AMD's new architecture will be found in the next-generation Opteron due out at the middle of this year. AMD will initially launch at speeds ranging from 2.1GHz to 2.3GHz, but by the end of this year you can expect higher clock speeds. On the desktop, AMD's Agena core will be a Barcelona equivalent shipping at between 2.7 - 2.9GHz. Kuma will be a dual-core variant of Agena shipping in the 2.0 - 2.9GHz range.
Barcelona will be a success for AMD; the long awaited architectural update to K8 should yield significant performance improvements, especially in current areas of weakness for the K8 (e.g. video encoding). Our review of the Athlon 64 X2 6000+ showed that with aggressive pricing, AMD could come close to offering something competitive to Intel. At current prices, we suspect that Barcelona would be enough to close the gap between AMD and Intel. Chances are that we won't see bargain basement prices on AMD's new cores, but we'd expect that AMD would have to maintain a competitive market.
The real catch here is what happens after Barcelona; as we mentioned before, Intel's current successes were born out of steady but regular evolution of a good starting architecture. With yearly updates to the Pentium M, Intel achieved a snowball effect that proved difficult to stop. It would seem that a similar approach by AMD would be necessary to avoid sticky situations like the one it finds itself in today.
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chucky2 - Friday, March 2, 2007 - link
Can you post the link that originates at AMD's own website then that says specifically that AM2+ CPU's are guaranteed to work - understandably maybe not supporting every new feature - in current AM2 boards?Not a news post from DailyTech, The Inquirer, Toms, whatever...one that's on AMD's site itself.
And No, AMD could make AM2+ completely incompatible with current AM2 boards and they probably wouldn't see much drop if at all from the large OEM's. The large OEM's would just ensure that when the AM2+ CPU's came in, AM2+ motherboards would likewise come in.
Believe me, I want to see the link...because I'm desperately awaiting 690G or MCP68, whichever comes first (which is probably MCP68 at the pace AMD is moving on 690G).
Chuck
yacoub - Thursday, March 1, 2007 - link
You say 128kb L1 per core but the diagram image just beneath that text shows a 64bit L1 cache. Please confirm which it is.
Thanks.
Awesome article, btw. Seems like quite a significant group of changes to the CPU. Looking forward to seeing how it stacks up against the best Quad Core2 Intel can offer. =)
yacoub - Thursday, March 1, 2007 - link
also, please forgive my hasty typing - I wrote "128kb" and "64bit" - I meant "128KB" and "64KB"JarredWalton - Thursday, March 1, 2007 - link
L1 is 128K total - 64K data and 64K instruction.Beenthere - Thursday, March 1, 2007 - link
AMD doesn't do knee-jerk reactions like Intel because AMD has superior products. AMD continues to take market share from Intel in every segment and Barcelona will continue that trend. Barcelona looks to be every bit as superior to Intel's hacked/patched/glued together chips as Opteron was when introduced. Intel's chips depend on huge cache size for their performance and that crutch won't work after the intro of Barcelona.For those without a clue, AMD didn't start design of Barcelona last week or last year. It's been in the development pipeline for many years and thr performance will demonstrate exactly why AMD's long term platform stability is the right choice for most enterprise buyers. Intel is gonna feel the pain again.
Roy2001 - Thursday, March 1, 2007 - link
Facts please, no BS.zsdersw - Thursday, March 1, 2007 - link
Idiocy incarnate.Regs - Thursday, March 1, 2007 - link
AMD, like Intel, start numerious projects. Just not all of them get to this finish line. Actually a lot of them don't even reach the end of the planning phase before being scratched.As for Intel and their large caches...well I'd say it's amazing how half their die (if not more) is used for cache and still had enough space for all the core logic that's kicking the crap out of the K8 now.
Common sense!
erwos - Thursday, March 1, 2007 - link
Looks like some good improvements coming down the pipe. The cache size issue makes me nervous, though - 512kb per core is starting to look a little antiquated, and there's no information about the bandwidth to the L3 cache (which, presumably, is slower than L2).SmokeRngs - Thursday, March 1, 2007 - link
In the past, AMD did not need the large cache sizes that Intel did for their processors. This was very obvious in regards to the Netburst architecture. However, while Core2 is much better than Netburst there are still disadvantages for Intel.I'll explain a little background as far as I understand it. In the K7 and Netburst days, Intel had to have the cache to make up for their long pipeline. Branch mispredictions are going to happen and the penalty on the long pipeline of the Netburst processors hurt their IPC badly. The shorter pipeline on the K7 did not have the same performance penalty due to the shorter pipeline. With K8, the on die memory controller also negated the need for large L2 caches due to the reduced latency when accessing main memory. This has been one of the major performance aspects for the K8 architecture.
The Core2 architecture obviously does not have the on die memory controller so the need for larger caches is still present and Intel sees improvement due to the larger caches. Barcelona still has the on die memory controller and the previous efficiency is still there and still negates the need for large caches. This is just the difference between architectures. While having a larger cache on the K8 did improve performance some in some usage scenarios, it wasn't on the same scale as the improvements Intel received with a larger cache.
AMD can't compete with Intel in regards to cache size. However, other architecture differences make up for the lack of large amounts of cache. Barcelona having a smaller cache does not seem to be a big problem. If it was a big problem, AMD probably would have gone with a larger cache to get the extra performance. Bigger does not always mean better or at least enough better to warrant the extra.
Smaller cache will mean fewer transistors which should mean better yields, lower power consumption and cheaper to produce.