AM2/Core 2 Duo Latency and Memory Bandwidth

The introduction of AM2 merely increased the AMD latency advantage. AM2 latency was slightly lower than DDR latency on AMD.

Memory Latency Comparison - Conroe & AM2

However, Core 2 Duo did what most believed was impossible in Latency. One of AMD's advantages is the on-processor memory controller, which Intel has avoided. It should not be possible to use a Memory Controller in the chipset on the motherboard instead and achieve lower latency. Intel developed read-ahead technologies that don't really break this rule, but to the system, in some situations, the Intel Core 2 Duo appears to have lower latency than AM2, and the memory controller functions as if it were lower latency.

Memory Bandwidth

The other part of the memory performance equation is memory bandwidth, and here you may be surprised, based on Conroe's performance lead, to see the changes Core 2 Duo has brought. Results are the average of ALU/FPU results on Sandra 2007 Standard (Buffered) memory performance test. We used the same memory on all three systems, and the fastest memory timings possible were used at each memory speed.


The results are not a mistake. In standard memory bandwidth, Core 2 Duo has lower memory bandwidth than either AM2 or Intel NetBurst. It is almost as if the tables have turned around. AMD had lower bandwidth with DDR than Intel NetBurst, and the Athlon64 outperformed Intel NetBurst. Now Conroe has the poorest Memory Bandwidth of any of the three processors, yet Conroe has a very large performance lead. It appears Conroe, with shallower pipes and an optimized read-ahead memory controller to lower apparent latency, makes best use of the memory bandwidth available.

Perhaps the most interesting statistics are that the huge increases in memory bandwidth brought by AM2 make almost no difference in AM2 performance compared to the earlier DDR-based Athlon64. With this perspective let's take a closer look at DDR2 memory performance on AM2 and Core 2 Duo. This will include as close to an apples-to-apples comparison of Core 2 Duo and AM2 as we can create.

DDR/NetBurst Memory Bandwidth and Latency Memory Test Configuration
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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.
    Reply
  • 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.
    Reply
  • 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
    Reply
  • 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. Reply
  • 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. Reply
  • 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. Reply
  • 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+) Reply
  • 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? Reply
  • bob661 - Tuesday, July 25, 2006 - link

    Thanks guys. I don't remember seeing info about memory either. Reply
  • 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. Reply

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