Despite the fact that the 45 nm Quad-core Opteron was the best server CPU at launch, a few months later AMD’s success was washed away by a tsunami called “Nehalem”. The Nehalem architecture combined subtle tweaks to an already superior integer engine with brute force tactics such as a triple channel integrated memory controller. The IMC delivered low latency and massive amounts of bandwidth thanks to the highest clocked DDR-3 DIMMs. But it was not enough for the ambitious Intel engineers. They added Simultaneous MultiThreading (SMT), and this was the final blow to any competition left standing in the server market. SMT or Hyperthreading as Intel calls it, boosted performance by 30% and more in key applications such as SAP, Oracle and MS SQL Server. The end result is that the current Xeon outperforms AMD’s best CPU’s by 60 to 85%! Historic, as Intel never had such a commanding lead since AMD entered the market with it’s Athlon MP.

One could start debating about some of the details of these benchmarks, but that would mostly be splitting hairs. Yes, these scores were obtained with DDR3-1333, while the vast majority of X55xx servers are equipped with DDR3-1066. And yes, power consumption of the fastest Xeons is about 20W higher per CPU than on the “Shanghai” Opterons. So in order to compare in the same power range, you should compare with the E5540 at 2.53 GHz. But even with DDR3-1066 and at 2.53 GHz, the latest Xeon would - roughly estimated – outperform the best quad-cores of AMD with 40 to 70%. The lead is even higher in bandwidth intensive applications. Only in the pretty rare dense matrix applications, with Linpack being the most popular benchmark, AMD could still make a point. AMD can deliver the same amount of Gigaflops at lower power consumption and a lower price. Nice, but we are talking about the 1% of the applications on the market. The other ray of hope for AMD was the competitive performance that the Opteron 2389 2.9 GHz delivered on ESX 3.5 on our virtualized benchmark vApus Mark I. But with ESX 4.0, the new Xeon “Nehalem” should widen the gap again thanks to better hyperthreading support and the fact that EPT is fully supported in the latest ESX hypervisor. AMD’s next generation CPU is scheduled to appear in 2012, so it looks like AMD will have to leave the high-end and midrange server CPU market to Intel. Unless…

Ever since the introduction of the 45 nm CPUs, AMD has been executing very well. So well, even, that it reminds us of the K75 times. You might remember how in October 1999, AMD introduced the “K75” in 250 nm and sped up the “x86-Alpha” to 1 GHz in March 2000, only 5 months later. It has indeed been 10 years since AMD has executed so well. Only six months after the successful launch of their 45 nm quad-core, AMD rolls out their hex-core “Istanbul” at 2.6 GHz well ahead of schedule. It is basically a “Shanghai” Opteron with 2 extra cores and a slightly tweaked memory controller. What is more impressive, though, is that AMD is capable of launching a hex-core at 2.6 GHz today, a CPU that consumes only a few watt more than the six month older quad-core at 2.7 GHz. Well done, AMD. But should the IT professional care about the new six-core of AMD? In which applications does it make sense to consider an “Istanbul” based server? Are two extra cores enough to bring back AMD’s Opteron on the specsheet of your next high performance server?

Do Six Cores Make Sense?

The question is not theoretical. When Intel launched their hex-core “Dunnington”, quite a few applications did not make good use of it. The quad-socket “Istanbul”-based servers will face the same problems as “Dunnington”: some server applications prefer “2n cores”, a few will not scale above eight cores and many will not get past 16 very successfully. Yes, even in the server world, quite many applications do not scale well beyond 8-16 cores. Mailservers, webservers and even some databases may be in that situation. If your database gets a lot of locks on the same amount of data, locking contention will kill off your performance once you get beyond a certain number of cores. Rendering applications are another group that start to show diminishing returns with more than 8 cores. It is pretty likely that clustering dual-socket quad-cores makes more sense that adding more cores to the same machine.

But the six-core “Istanbul” CPU has advantages too. The Nehalem Xeon offers 8 logical cores, but the two threads on each core have to share the 32 KB L1 and the tiny 256 KB L2. Istanbul can work with “only” 6 threads, but each thread gets a 64 KB L1 and an in comparison copious amount of 512 KB of L2. In a nutshell, It is clear that the new AMD “Istanbul” Opteron targets a specific market: a few compute intensive HPC applications, large databases and most importantly: “heavy” virtualized workload. The reason why we say “heavy” is that the six-core is a drop-in replacement for the current quad-core Opterons. That means that the memory capacity of the servers based on the new six-core will probably be the same. If you are consolidating lots of light loads together, you are likely to run into memory limits before you run into processing power limits.

Istanbul's Improvements
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  • solori - Tuesday, June 2, 2009 - link

    I should have said "abundant (cheap) memory."
  • mkruer - Monday, June 1, 2009 - link

    I am disappointed that you did not bench X5550 vs 2435. This is the chip that the Opteron 2435 was designed to go up against, not the X5570 which is clocked 300MHz higher and 40% more expensive. Heaven forbid that you try to include chips at the same price point. That being said other sites that did compare based upon price, and not top of the line, show that the Opteron 2435 is indeed comparable to the X5550 at the same price point and speed. Now if AMD can up the speed of the hex core, then it will be a more direct comparison to the X5570. The X5570 is 50% faster but it is also >50% more in cost.
  • mino - Wednesday, June 3, 2009 - link


    Actually, I have no qualms with comparing the best with the best, but the commentary is mostly out-of-place.
    I guess this was written after 3 days without sleep, but anyway.

    After an excelent vAPUS Mark 1 article I would expect better that old-school style:
    "1000 $ Pentium 4 3.2 EE is clearly (15%) better than $400 Athlon 3200+ so Athlon is clearly a piece of junk. Well maybe for games not so much but generally it is a piece of junk."

    Thank god the numbers tell their own story.
  • JohanAnandtech - Wednesday, June 3, 2009 - link

    It seems that some people like to create the impression that we did not take into account that both CPUs were not at the same pricing.

    [quote]"However, as the Opteron 2435 competes with 2.66 GHz Xeon and not the Xeon 2.93 GHz, this is the first benchmark where “Istanbul” is competitive."[/quote]">
    [quote]"The Nehalem-based Xeon moves forward, but does not make a huge jump. Performance of the six-core Opteron was decreased by 2%, which is inside the error margin of this benchmark. It is still an excellent result for the latest Opteron: this results means it will have no trouble competing with the 2.66 Ghz Xeon X5550. "
    [quote]"The new Opteron 2435 at 2.6 GHz was a pleasant surprise on vApus Mark I: it keeps up with more expensive Xeons on ESX 3.5 update 4 while consuming less, and offers a competitive performance/watt and performance/price ratio on vSphere 4. The six-core Opteron is about 11 to 30% slower on vSphere 4 than the 2.93 GHz Xeon X5570 but the overall cost of the Istanbul platform is significantly lower (DDR-2 versus DDR-3) and the 2.6 GHz 2435 consumes less power in a virtualized environment "

    And I have confidence that the vast majority of my readers are intelligent people who can decrease the benchmarks with 8 to 10% to see what a Xeon x5550 would do
  • mino - Thursday, June 4, 2009 - link

    No, I do not like that, nor like to create such an impression.

    The article presents the numbers reasonably well for me. It is just that your (justified) love for Nehalem is glowing through and many, many comments were out of place.
    I believe this was not intentional but cause by your love for the Nehalem platform which is otherwise great.

    All the numbers tell one thing - Istanbull is generally on par with Nehalem clock for clock +- 10% depending on the workload.

    About that glowiong love for Nehalem:
    >>>MCS eFMS 9.2
    "A single 8-thread Xeon X55xx is by far the best choice here."

    Why ? There is no 1*2435 number.
    Based on the numbers published single 2435 will get about 55-58rps which for all practical needs is identical performance to _flagship_ Nehalem.

    >>>3ds Max 2008 32b
    "We are sure that there are probably more efficient render engines out there, but it is simply not a market the AMD six-core should cater to. Nehalem-based Xeons are simply way too powerful for this kind of application. Render engines scale almost perfectly with clockspeed. So if cost is your main concern, consider the Xeon E5520 at 2.26 GHz, the cheapest CPU that still supports HT. We will test this one soon, but we expect it to deliver 67 frames per hour, which is still more than 20% better than any Opteron."

    OK, so first bash(rightfully) the application fo it rigid resource use pattern, than say that for Nehalem is "way too powerfull for this KIND of application" for Opteron to compete with.
    You managed to contradict your own reasoning to promote Nehalem for rendering while the numbers speak about single improperly optimized app.
    Which it is pretty certain SW vendor will take care of in due time. These numbers are just a result of no (affordable) 6-core presence on the market up to now.

    By these 2 comments you took the article balance from "Instanbul is generally about 5% slower per_clock than Nehalem, in certain apps it is on par or better while in other loses about 15%" - which is what the numbers tell - to "Instanbul is good for VMware, forget about it elsewhere".

    Which is about as much bad publicity you could give to the second fastest CPU on the market by_large_margin.

    Fact is, at a given price, Nehalem box is ALMOST IDENTICAL performance-wise to Istanbul box. While both crush everything else on the market by 30+ %.
  • lopri - Monday, June 1, 2009 - link

    Page 2, "..The most recent data is however in CPU’s L2-cache" I think you meant CPU #2?
  • JohanAnandtech - Monday, June 1, 2009 - link

    Yes, good catch. Fixed the issue.
  • classy - Monday, June 1, 2009 - link

    I skipped right to the virtualization portions. It is by far becoming the most dominate criteria for most of the IT world. The 6 core opty looks solid there, so it will come down to price. Now with the quickly developing virtual desktop infrastructures, how well a platform does virtualization makes it just two fold more important. Many folks have already virtualized mission critical apps. I know we're doing exchange in the near future. The days of seperate physical servers and desktops are going the way of the dodo bird. Its becoming all about virtualization.
  • genkk - Tuesday, June 2, 2009 - link

    why power consumption not shown here....the bench mark guys in anandtech lost the papers...or they don't want you to see

    any way go to where istanbul wins
  • JohanAnandtech - Tuesday, June 2, 2009 - link

    More detailed power consumption numbers will be available in the next review.

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