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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  • TonyB - Tuesday, July 25, 2006 - link

    so ive been hearing a lot of people use this argument, "oh competition is good, i can get a so-and-so cpu now for xyz price!!". what an incredible value!

    cant you bring that a notch higher and say, "dang, Intel just whooped AMD, i'm going to purchase an amd K6-2 400mhz cpu now for $5" yes! horray for competition! what an incredible value only $5!

    at what point does reality set in that you're investing in obsolete technology? or does the old rationale, "i dont want the fastest, this old crap is good enough for me" still apply.
  • OcHungry - Wednesday, July 26, 2006 - link

    You waited 4 years to say that "crap" about AMD's bargain value? but please dont tell us about your 4 years venture in finding a better way to exhust your P4 hot air.
    very nice.
  • Calin - Wednesday, July 26, 2006 - link

    Unfortunately, the current production processors don't reach that low a value (the AM2 semprons have a price of around $70+, and the Socket A semprons have a price of around $50). You might want to invest in new obsolete technology (with a longer warranty), or you might want to invest in old obsolete technology (or in old current technology, see refurbs).
    As long as your performance needs are reached, you could be certain to a degree that a failure in your computer could be repaired/replaced in short time, you are ok to go with Pentium MMX or so processors. Anyway, finding SDR RAM for your K6-2 might not be so easy (and SDR DIMMs were a new memory standard then). Good luck finding enough SIMMs to put the memory at 128MB
  • BPB - Tuesday, July 25, 2006 - link

    How about an article spending $200 on both the CPU and video card ($400 total) and then look at what various motherboard and memory combos get me. You could spend $100 to $250 on motherboards and show me what I get, with memory hopefully being the same for the Intel and AMD systems. That's really the bottom line for myself and many, many others. Many if not most of us set a price range for CPU, video card, and memory and then go from there. Either that or simple overall cost is set. I know you give us buying guides where you spend X amount on systems, but I don't think you show us the power each system gets.
  • photoguy99 - Tuesday, July 25, 2006 - link

    They already have those articles - They periodically release CPU and Graphics card guides that analyze the bang for the buck at different budgets.
  • BPB - Tuesday, July 25, 2006 - link

    I know they do that, but I don't think I've seen both "here's what $1000 gets for an AMD/Intel system" and "here's how fast each system is". That's what I'd like to see. I know how much individual parts cost and how fast they are in and of themselves, but put it all together and show me systems and compare those systems. If they've done that in the past I've missed it. But the past no longer matters, so I'd love to see one that's current as of today's new prices.
  • Calin - Wednesday, July 26, 2006 - link

    The computer price guides did just that - taking a budget of $$$ or $$$$ and building systems. There was the budger guide, gamer guide and "all out" guide (this last one had price ranges at $2000+)
  • bob661 - Tuesday, July 25, 2006 - link

    What was the purpose of this article? Was there something that was left out of the tons of earlier benchmarks from various websites?
  • bob661 - Tuesday, July 25, 2006 - link

    Thanks guys. I don't remember seeing info about memory either.
  • rjm55 - Tuesday, July 25, 2006 - link

    There were a lot of things that I hadn't seen anywhere else. No one I have read shows that Conroe is lower in Bandwidth than either AM2 or Netburst. I find that surprising looking at Conroe's big performance lead. This is also the first time I've seen AM2/Conroe compared clock-to-clock in the same configuration using the same memory/settings - and at 2.93GHz. The new graphs for memory speeds show directions and provide more info that bar charts. Suggest you use them more in other reviews.

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