Core 2 Duo (Conroe) launched about twelve days ago with a lot of fanfare. With the largest boost in real performance the industry has seen in almost a decade it is easy to understand the big splash Core 2 Duo has made in a very short time. AnandTech delivered an in-depth analysis of CPU performance in Intel's Core 2 Extreme & Core 2 Duo: The Empire Strikes Back. With so much new and exciting information about Conroe's performance, it is easy to assume that since Core 2 Duo uses DDR2, just like NetBurst, then memory performance must therefore be very similar to the DDR2-based Intel NetBurst architecture.

Actually, nothing could be further from the truth. While the chipsets still include 975X and the new P965 and the CPU is still Socket T, the shorter pipes, 4 MB unified cache, intelligent look-ahead, and more work per clock cycle all contribute to Conroe exhibiting very different DDR2 memory behavior. It would be easy to say that Core 2 Duo is more like the AMD AM2, launched May 23rd, which now supports DDR2 memory as well. That would be a stretch, however, since AM2 uses an efficient on-processor memory controller, and the launch review found Core 2 Duo faster at the same clock speed than the current AM2. This is another way of saying Conroe is capable of doing more work per cycle - something we had been saying for several years about Athlon64 compared to NetBurst,

The move by AMD from Socket 939 to Socket AM2 is pretty straightforward. The new AM2 processors will continue to be built using the same 90nm manufacturing process currently used for Athlon 64 processors until some time in early to mid-2007. AMD will then slowly roll-out their 65nm process from the bottom of the line to the top according to AMD road-maps. This could include memory controller enhancements and possibly more. Performance of AM2 only changed very slightly with the move to DDR2, generally in the range of 0% to 5%. The only substantive difference with AM2 is the move from DDR memory to official AMD DDR2 memory support.

Our AM2 launch reviews and the article First Look: AM2 DDR2 vs. 939 DDR Performance found that AM2 with DDR2-533 memory performed roughly the same as the older Socket 939 with fast DDR400 memory. Memory faster than DDR2-533, namely DDR2-667 and DDR2-800, brought slightly higher memory performance to AM2.

The Core 2 Duo introduction is quite different. Clock speed moved down and performance moved up. The top Core 2 Duo, the X6800, is almost 1GHz slower than the older top NetBurst chip and performs 35% to 45% faster. With the huge efficiency and performance increases comes different behavior with DDR2 memory.

With the world now united behind DDR2, it is time to take a closer look at how DDR2 behaves on both the new Intel Core 2 Duo and the AMD AM2 platforms. The performance of both new DDR2 platforms will also be compared to NetBurst DDR2 performance, since the DDR2 NetBurst Architecture has been around for a couple of years and is familiar. We specifically want to know the measured latency of each new platform, how they compare in memory bandwidth, and the scaling of both Core 2 Duo and AM2 as we increase memory speed to DDR2-1067 and beyond. With this information and tests of the same memory on each platform, we hope to be able to answer whether memory test results on Conroe, for instance, will tell us how the memory will perform on AM2.

In addition we have an apples-apples comparison of AM2 and Core 2 Duo running at 2.93GHz (11x266) using the same memory at the same timings and voltages with the same GPU, hard drive, and PSU. This allows a direct memory comparison at 2.93GHz at DDR2-1067. It also provides some very revealing performance results for Core 2 Duo and AM2 at the exact same speeds in the same configurations.

DDR/NetBurst Memory Bandwidth and Latency
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  • duploxxx - Thursday, July 27, 2006 - link

    please give us edit...

    powerconsumption is only less in 100% load.... when powermode kicks in the amd is much less consuming... how long do you think a system runs in powermode against full load....
    Reply
  • duploxxx - Thursday, July 27, 2006 - link

    wrong... the conroe gains from the memory speed the amd more thats a fact... the ones you are referring to are probably 4200 and 5000, well we can say that they perfrom better when using 533/667 because then they don't have the devider issue running the memory on 742 in stead of 800.

    so the performance/price ratio on those chips is better with 553/667
    Reply
  • zsdersw - Thursday, July 27, 2006 - link

    Conroe's performance isn't merely a function of memory bandwidth or memory speed. Reply
  • PeterR - Tuesday, July 25, 2006 - link

    If you could actually go out and BUY one ?

    Peter R.
    Reply
  • michal1980 - Tuesday, July 25, 2006 - link

    Wow. AMD fanboi's pulling out all the crap that the intel fanboi's have pulled in the past.


    wake up!. Right now, Intel core 2 duo is faster then AMD 64 right now.

    Its like video card fanboi's but worse, because the difference here is clear.

    If I was building a gaming rig this year, I would build with a core 2 duo.

    Just like a few months ago, it would be with an AMD 64.

    I go with what company is faster. I used both nvidia cards, and ati Cards. I use pentiums, and p2's, I used athlon xp's when you over clock them 50% ease and they were dirt cheap. I use a opty dual core right now because it was faster then the p4's. I use p-m lappys because of performance/battery life.

    If I was building a rig right now. I'd switch to an intel Core 2 duo. Why? because its faster. I could care less about who makes it.

    if apple comes out tommorow with a magic pc that runs all pc games run 20% faster, I'm buying an apple.
    Reply
  • Pirks - Tuesday, July 25, 2006 - link

    quote:

    if apple comes out tommorow with a magic pc that runs all pc games run 20% faster, I'm buying an apple
    I'd buy a iMac or Mac Pro right this second if it were running all PC games at all without rebooting between OS X and XP.
    Reply
  • yacoub - Tuesday, July 25, 2006 - link

    Two things:

    1 - I think I like the new font used in tables and charts.

    2 - In the SuperPi chart you say Lower is Better but then inverse the graph such that it is actually the line higher on the graph that is better. Unless the reader looks closely at the numbers, they could infer that the AMD chip wipes the floor with the Conroe.
    Reply
  • redbone75 - Tuesday, July 25, 2006 - link

    Seriously, though, here we have a completely new architecture from Intel, the same Intel that is this massive company with enormous resources and huge R&D departments, and these AMD fanboys are still all upset because Intel has not only achieved parity with but also exceded AMD in performance. Come to think of it, this is the exact same argument that AMD fans were using when preliminary benchmarks came out on Conroe. "It's not fair to compare Intel's new architecture to AMD's old one, because they have an advantage." Hey, you want some cheese with that wine? I'll tell you what: AMD enjoyed the performance lead for a while. Now, Intel is having a go at it and, with any luck, AMD will come out on top in the future, at least I really hope so. Why do I hope so? Do any of you think AMD would have lowered their processor prices so much if Conroe wasn't such a threat? Do you think Intel would have released Conroe at these prices if they didn't have to take back the crown from AMD? Hey, with the X2's we still get a great range of processors at much lower prices. Hell, even the Pentium D's are going to be attractive at lower prices. That makes me happy, not some benchmarks saying this processor is faster than that processor. And really, I don't know about you but I don't care about which processor wins memory latency benches, I only care about the end performance in applications I actually use. Reply
  • DigitalFreak - Tuesday, July 25, 2006 - link

    Amen, brother! Reply
  • TravelMug - Tuesday, July 25, 2006 - link

    As said by several people before - you are not testing latency but the prefetch abilites of the CPU. Same has been said about the original Conroe article, you don`t seem to listen though.

    "Everest from Lavalys shows latency improvements in the new CPU revisions, but it shows Latency more as we would expect in evaluating Conroe. For that reason, our detailed benchmarks for latency will use both Everest 1.51.195, which fully supports the Core 2 Duo processor, and ScienceMark 2.0."

    Really? That is a 2 years old version, there have been countless new version since then. Also, if that version "fully supports" the Core 2 Duo processor, how come this is what the developer says about the latest version 3.01?:

    http://www.lavalys.com/products/whatsnew.php?pid=3...">Support for Intel Core 2 "Conroe" and "Merom" processors
    Reply

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