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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  • Calin - Wednesday, July 26, 2006 - link

    I wonder if Conroe is losing a part of its bandwidth to the prefetcher. It might be so (the prefetcher is busy bringing things that will be or won't be needed, and discards some of them. Meanwhile, the memory bandwidth usable decreases). Reply
  • defter - Tuesday, July 25, 2006 - link

    I don't recall that other benchmarks contained DDR2-400, DDR2-533, DDR2-667, DDR2-800 comparison.

    Basically, this review shows that if you don't want to pay a big premium for DDR2-800, Conroe is even more attractive. This isn't very suprising, because Conroe's 1066MHz (8.4GB/s) FSB can be saturated by dual-channel DDR2-533 (2x4.2GB/s = 8.4GB/s).
    Reply
  • classy - Tuesday, July 25, 2006 - link

    The Conroe buying guide was a great article, much like the Anandtech of old. But this review is too much like the recent ones absolutely of little or no value. What was the purpose of this read? We know already know core is faster.....we know already know as it is has been shown numerous times around the net memory scaling. Where is the originality at anymore? Want an example? There is a clear price difference between the two now. If a person goes AMD, they will be able to afford a better graphics card then say someone who goes Core. So why not a comparison along those lines. There is so much more to the puzzle then the same old lets run some benchmarks. Reply
  • bob661 - Tuesday, July 25, 2006 - link

    I would like to see more articles on memory and motherboards myself for the Conroe. Reply
  • Wesley Fink - Tuesday, July 25, 2006 - link

    From the conclusion : "The deep price cuts announced by AMD yesterday will definitely help. The new numbers indicate AM2 will be very competitive at the low end to low-mid of the processor food chain - a spot they have held in the past and where they have still managed to survive. The low end looks very competitive, and AMD is positioned close enough to mid-range in performance to keep Intel honest. There is no mistaking, however, that Intel Core 2 Duo owns the mid to high-end of the current processor market."

    Reply
  • OcHungry - Wednesday, July 26, 2006 - link

    Now wait a minute- The E6800 costs ~ $1200 (if you find one), the FX62 is $800, which is 50% less. According to your review/benchmarks you propose E6800 is about 20% better performer than FX62. Considering price/performance ratio, FX62 should be the ideal choice for high end users/enthusiasts as far as price/performance is concerned.
    Am I wrong? This is without considering motherboard and video card limitation(s) of Intel platform. The high end enthusiasts would not run single graphic card or IGP system. Have you figured into price/performance of CPU, Motherboard and video card? Or SLI and Crossfire?
    What about 4x4?
    AMD is releasing 4x4's on several x2 CPU's (I think other than FX62) that will cost less than $1000. Are you saying a $1200 E6800 is a better performer than a less than $1000 4X4?
    wouldn’t a 4x4 make the top end of the enthusiast’s market?
    In my country a 4x4 make a stronger candidate for "the new king to be born".
    Reply
  • DigitalFreak - Tuesday, July 25, 2006 - link

    Give up, Wesley. :-)

    The AMD fanboys will keep trying to destroy your conclusions, since it doesn't benefit them.
    Reply
  • duploxxx - Tuesday, July 25, 2006 - link

    why would they, you might call me a fanboy but for sure the statement of wesley is true.
    the high performanmce market is for now (ehh from the moment you can buy them) back at the intel site... (the low-mid market is for both altough amd has an advantage here on lower price in combination with lower price on mobo's and global availability) the perfromance crown for the e6700 and xe6800and will remain there until amd pulls out something new, even if it is by 4x4... perfromance crown is performance crown... some people just do and buy anything as long as it is the fastest... same with gpu cards.. they'll buy them every month.
    Reply
  • drebo - Tuesday, July 25, 2006 - link

    quote:

    the high performanmce market is for now (ehh from the moment you can buy them) back at the intel site...


    If you consider an Athlon64 X2 5000+ or FX-62 "low-mid" tier performance, I suppose you could come to this conclusion.

    Fact is, on a dollar-for-dollar basis, AMD still leads in, or atleast matches, performance. If I look at my main processor vendor's future pricing on Core 2 Duo processors(they're not scheduled to get any in until August 18th, by the way) and compare them with Athlon64 X2 processors under the new pricing scheme, this is what it looks like:

    Athlon64 X2 3800+ @ $149
    Athlon64 X2 4200+ @ $183
    Core 2 Duo E6300 @ $199.58
    Athlon64 X2 4400+ @ 219.79
    Athlon64 X2 4600+ @ 235.00
    Core 2 Duo E6400 @ 239.58
    Athlon64 X2 4800+ @ 279.74
    Athlon64 X2 5000+ @ 294.74
    Core 2 Duo E6600 @ 334.32
    Core 2 Duo E6700 @ 553.26
    Athlon64 FX-60/62 @ 811.00
    Core 2 Duo X6800 @ 1021.68

    Now, that gives us a few pairing(on which Athlon64 X2 processors always come out below) by which to compare: 4200+ vs E6300, 4600+ vs E6400, 5000+ vs E6600. Now, according to Anandtech's own Conroe vs Athlon64 benchmarks, the Athlon64 meets or exceeds the corresponding Conroe processor in probably 90% of the non-synthetic benchmarks. THIS is the important thing. I can take an FX-60 and just as easily compare it to a Pentium D 930 and say that the FX-60 is better, discounting the fact that the FX-60 is nearly 4x the cost.

    The same is true here, and I've seen countless review sites doing it. Yes, the E6700 and X6800 processors outperform anything AMD has to offer, but they also cost more than anything AMD has to offer. AMD no longer has a processor at the $1000 price point, and down the line, AMD processors consistently cost less than Core 2 Duo processors they perform just as well against. It is this that is the important thing and it is this than none of the review sites or press has addressed. AMD is still quite competative dollar-for-dollar, particularly when you factor in motherboard cost.
    Reply
  • coldpower27 - Tuesday, July 25, 2006 - link

    Try meets or is slightly behind. AMD processors rarely "exceeds" in real world applications in the slightest.

    an E6600 is faster then the 5000+

    an E6400 is faster then the 4600+

    and E6300 is faster then the 4200+

    as has been shown by Anandtech.
    Reply

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