The technology launch of Intel's new G35 chipset - the first to support DDR3 - occurred just 3 days ago. At launch most reviewers were intrigued by the potential of DDR3 but less than excited about the high latencies and high prices that were available at launch. As you saw in Intel P35: Intel's Mainstream Chipset Grows Up and Intel P35 Memory Performance: A Closer Look our first two samples of DDR3 were rated at DDR3-1066 and 7-7-7-20 timings. These DIMMs would also run at DDR3-1333 with 9-9-9-25 timings. While performance at both speeds was promising, we were left to wonder when lower latency DDR3 might become available.

The higher latency DDR3 at launch certainly gave the top DDR2 a run for the money, but it generally took much higher speeds to match or surpass current DDR2 with low latency timings. It was clear lower latency would bring DDR3 much improved performance and make it even more attractive to buyers, but we assumed it would likely be months until we saw lower latency DDR3 - as it was in the launch of DDR2.

With this scenario, imagine our surprise when Kingston asked us if we would like to review their first low-latency DDR3. Where the competition was 9-9-9 at DDR3-1333 and 7-7-7- at DDR3 1066, Kingston specified their new DDR3 memory at 7-7-7 at 1333 and 6-6-6 at 1066. These were definitely some memory sticks we wanted to review.

If these numbers still seem high to you, you need to back up a bit for a larger perspective. While lower speed DDR2 can have latencies as fast as 3, DDR3 starts at 800 and the boards we have seen only allow CAS latencies as low as 5. The CAS range on better P35 boards is normally 5 to 10. Given this range of available latencies at higher speeds than DDR2, it is clear the new Kingston KHX11000D3llK2/2G has found ways to provide the lowest latencies so far in DDR3.

Keep in mind that the actual latency in nanoseconds is what really matters, so while the number of memory cycles from DDR2-533 CL3 through DD2-667 CL4, DDR2/3-800 CL5, DDR3-1067 CL7, and DDR3-1333 CL9 increases, the actual latency in ns only ranges from 11.25ns (DDR2-533 CL3) to a maximum of 13.5ns (DDR3-1333 CL9). While CL7 may sound like a high latency, achieving that with 1333 MHz memory is actually results in a time latency of 10.5ns, and of course that's with much higher bandwidth than some of the other memory speeds.

We presented detailed comparisons of memory performance on the current P965, DDR2 on the P35, and DDR3 on the P35 just last week. This allowed us to run a full suite of comparison tests using the same configurations used in Intel P35 Memory Performance: A Closer Look. Those wondering whether DDR3 can compete with low-latency DDR2, and when that might happen will get some answers to their questions in this comparison.

Kingston KHX11000D3LLK2
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  • Wesley Fink - Thursday, May 24, 2007 - link

    We ran a complete test suite at DDR3-1500 7-7-7-15. Not surprisingly ALL of the results were a bit higher than those reported at 1520 9-8-8-22.

    As a result we will be replacing the 1520 results on all performance charts with the higher 1500 7-7-7 results. Give us about 15 minutes to complete the update. Enjoy!
    Reply
  • photoguy99 - Thursday, May 24, 2007 - link

    It would be a good accomplishment for Barcelona to come out and surpass Core2 performance that wowed the world last year.

    But how many of these can Barcelona beat:
    1) Original Core2 Quad at 2.66Mhz (probably what they were aiming for)
    2) Add P35 chipset for 5-10% performance increase
    3) Add DD3 at 1333Mhz or higher with low latencies for 5-10% increase
    4) Add Penryn core for 5-10% performance increase at same clock speed
    5) Penryn releases at 3.2 Ghz, add another 10% increase

    When is the pain gonna stop for AMD?

    It seems by this fall the Intel platform is going to be a lot faster that the original Core2 or Core2 quad releases.
    Reply
  • defter - Friday, May 25, 2007 - link

    quote:

    5) Penryn releases at 3.2 Ghz, add another 10% increase


    Since Intel has already demonstrated air-cooled 3.33GHz Penryn based quad cores, and desktop Penryn based CPUs will use 1333MHz FSB and support half multipliers, I guess that desktop Penryn based quad core CPUs can be launched at least at 3.33-3.5GHz if necessary.
    Reply
  • TA152H - Thursday, May 24, 2007 - link

    OK, this post really irritates me.

    You think AMD started design on the Barcelona last year? How else could you possibly say they were aiming for the 2.66 Core 2 before it was even released if this wasn't true? Good grief, think!

    The P35 most certainly does NOT add 5-10% application performance. Maybe in specific applications you will see something like this, but overall, it's not that high.

    DDR3 at 1333 isn't adding much of anything right now. 5-10%???? Where are you getting these numbers from? In fact, in every gaming benchmark they ran, it was either slower or the same as the DDR2-1066. 5-10% my ass.

    Penryn numbers are also made up, it would be extremely optimistic for 5-10% increase in IPC for most applications. Maybe a few will, but broadly, it's probably not true, and absolutely speculative.

    Hmmmm, going from 3.0 GHz they have out now, to 3.2 GHz is 10%? I think it's more like 6.67%.

    In short, all your assumptions are either, at best speculative, or at worst, just wrong.

    Will DDR3 timings go down? Of course, but so will DDR2 since that's the dominant memory. Considering the changes to the Barcelona memory controller, I think you can expect a pretty substantial improvement there, but we won't know until we see it. A lot of stuff we won't know until we see it.

    The big thing that bothers me is AMD still has not fully implement memory disambiguation, and while the scheduling of loads is improved to P6 levels, I'm not sure if it's enough. I'm also not crazy about their substantial x87 implementation, as it's a deprecated technology and more and more becoming dead weight. It's not even part of x86-64.

    So, I'm not saying Barcelona will be better or worse, we'll see soon enough, but the reasons you give are, at best, specious, and at worst pure nonsense.

    Reply
  • yacoub - Thursday, May 24, 2007 - link

    I would guess they would aim for 20-25% improvement over last year's core2duo so somewhere around 3-4 of your 5 should be the level of Barcelona performance if it works out. In that case since I don't think you won't see all 5 of those combined this year, especially at a competitive price-point I think Barcelona still has a chance. =) Reply
  • Anonymous Freak - Thursday, May 24, 2007 - link

    One of my big gripes with the DDR3 reviews so far, which were the same when DDR2 first came out, is the direct comparison of same-bus-speed results. Of *COURSE* DDR3 at 800 MHz will be slower than DDR2 at 800 MHz. As this review shows, even the best DDR3 timings are slower than the best DDR2 timings.

    But, that's not what DDR3 is designed to do. It's designed to have higher latency in exchange for significantly higher bus speeds, as this test shows. You should be comparing the DDR3-1333 results with the DDR2-800 or 1066 results.

    Just as when DDR2 came out, it had much higher latency than DDR1, but faster bus speeds. Try comparing a top of the line DDR2 rig to a top of the line DDR1 rig now. (Say AMD AM2 vs. 939.) The faster bus speed of the DDR2 rig will just blow away the DDR1 rig, regardless of how good the DDR1 timings are. The same will be true with DDR3. Faster timings will come, as will faster bus speeds. The two will cause DDR3 to completely dominate even the fastest overclocked DDR2. Just look at this review, we have fast, but *within spec* DDR3 performing the same as the ultimate in overclocked DDR2. Just wait until we have the equivalent ultra-high-end DDR3 running at a *fully within spec* 1600 Mhz with 5-3-3 timings; and we'll probably see overclocked settings even higher.
    Reply
  • lopri - Friday, May 25, 2007 - link

    I'm afraid that your assertion is not quite the reality. AM2 CPU's memory controller has never been up to the level of Socket 939 CPU's. Under the same configuration sans memory, Socket 939 rig will always win over Socket AM2 rig. Reply
  • takumsawsherman - Thursday, May 24, 2007 - link

    I doubt you will actually see a significant difference between DDR and DDR2 running on otherwise similar chipsets. It wasn't very difficult to find 2-2-2-5-1 or 2-2-2-6 latencies with DDR memory. Even now, I am finding it hard to consistently source DDR2 for a reasonable price that has a reasonably low latency. But if you were to take 2-2-2-5-1 DDR and 3-4-3-9 DDR2 module pairs and run them with similar chipsets, with the same processors, you may in fact get some victories for DDR in your benchmarks.

    Bandwidth isn't everything. For some tasks, latency is far more important. Therefore, it is vitally important for someone to actually test real world scenarios and publish results. That way, people can save their money for an upgrade that might have a chance at improving their performance.
    Reply
  • bobsmith1492 - Thursday, May 24, 2007 - link

    Don't forget... latency is not just the CAS number; it is a function of the clock speed and the number of cycles of latency. The overall latency time is the important part. DDRII 800MHz at CAS3 will have better latency than DDRI 400MHz at CAS2 (if either of those exist even...) Reply
  • Chunga29 - Thursday, May 24, 2007 - link

    Those both exist as unofficial RAM speeds, though the DDR is harder to find these days. Reply

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