Stock Memory Performance

Most of today's motherboards that support DDR2 provide a wide range of memory ratios that match available DDR2 memory. End-users can select the memory ratio that matches their DDR2 memory speed. AnandTech memory testing uses the same approach. Benchmarks are run at all of the stock ratios at the fastest stable timings that can be achieved at the given ratio. With ratios, CPU speed remains the same at 2.93GHz in the memory test bed, and memory speed is varied by selecting different ratios.

The memory controller for Intel Socket T (Socket 775) motherboards is in the chipset, instead of part of the processor as in AM2 systems. Therefore, there is the potential for some ratio variations in memory performance. There is theoretically a small performance penalty for speeds other than a 1:1 ratio (DDR2-533 in this case) on boards designed for Intel processors. However, the actual performance penalty has been found to be very small with minimal impact on test results. As a result memory scales well through the various speed options.

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DDR2 memory is then pushed from the highest stock ratio that could be achieved in testing - normally 1067 - to the highest FSB speed at the stock multiplier. Unfortunately, the Corsair Dominator 10000 was not really stable above 1067 on the 975X. Speeds from 1090 to 1311 were attempted at 5-5-5-18 and 5-6-6-18 timings at the highest 2.35V to 2.4V that can be set on the ASUS P5W-DH. None of the settings was completely stable. Since anything below this range could not possibly outperform DDR2-1067 at 4-4-4-11 timings we made no further attempts to find the best performing overclock on this board.

The Corsair Dominator PC2-10000 is clearly not tweaked for the 975X chipset, and it performs much better on the NVIDIA 680i and the more recent P965 chipset motherboards. In the range from DDR2-400 to DDR2-1067 on the 975X board the Corsair Dominator 10000 performed very well - matching in most cases the best timings we have been able to achieve on the ASUS P5W-DH. The only exception was DDR2-1067 where the Dominator 10000 required 4-4-4-11 timings for stability compared to 4-4-3-11 with Dominator 8888 and OCZ Flex XLC9200. The Corsair Dominator 10000 does fine on the 975X at stock settings to 1067, but it was clearly designed for overclocking on the 680i and some P965 chipsets. It cannot be pushed anywhere even close to the rated DDR2-1250 on the ASUS 975X board.

It was time to see where this memory could go on the NVIDIA nForce 680i chipset - a chipset that had exhibited some stellar overclocks in our initial chipset launch review and with recent reviews of Dominator PC2-8888 and OCZ Flex XLC. Overclocking on the NVIDIA 680i was much more satisfying, as the Corsair Dominator easily met its rated speed and went far beyond, setting new speed records in several areas.

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On the nForce 680i the Corsair Dominator 10000 was completely stable at its rated speed of DDR2-1250 at 5-4-4-12 timings at the rated 2.4V. These are much better timings than the rated 5-5-5-18 at this 1250 memory speed. On air cooling, Dominator 10000 reached a stable DDR2-1315, which matches the highest speed we have ever reached with any DDR2 memory. This was only slightly higher than the DDR2-1300 reached by OCZ Flex XLC, and exactly the same 1315 reached with the sister Corsair Dominator PC2-8888. Despite the much higher rated speed of DDR2-1250, the Dominator 10000 topped out at the same DDR2-1315 found with the Dominator DDR2-1111 (PC2-8888). The binning and slightly slower timings certainly support an easy DDRR2-1250 on the NVIDIA 680i, but this higher rated 2GB kit tops out at the same maximum memory speed as the slower rated DDR2-1111, also from Corsair.

Memory Test Configuration Memory Bandwidth Scaling


View All Comments

  • OBWan - Wednesday, November 14, 2007 - link

    It appears that the "highest memory speed" chart on page 7 is not an objective comparison. Besides the top 3 bars that were tested with the overclock-friendly 680i platform, all the rest were tested with old chipsets e.g. 975X. The old chipsets actually hindered the max overclocking potential of those other DDR2's while at the time of their reviews, the editors believed those DDR2's had reached their speed limit, which was an unsighted mistake. So please delete this biased comparison chart and re-do all the tests with the same 680i platform. The readers in this forum deserve not to be cheated. Reply
  • yacoub - Thursday, February 1, 2007 - link

    If those timings relax much more, they'll be asleep.
    5-5-5-18? hehe =)
  • phil verhey - Thursday, February 1, 2007 - link

    i had buffalo pc2-10000 3.5 months ago.. and i still overclocked it to 1300mhz at 5-5-5-18 .. talk about an either ignorant, or biased article. Reply
  • Wesley Fink - Friday, February 2, 2007 - link

    The Buffalo 10000 was announced in Japan a couple of months ago, and it was widely reported that DDR2-1200 and DDR2-1250 were "coming". We have reviewed Buffalo memory in the past and we have yet to receive Buffalo PC2-10000 samples for review. We also have not seen a single review of Buffalo PC2-10000. PC2-10000 is also not listed on the Buffalo website - the highest rated Firestix there are PC2-8500.

    The Corsair PC2-10000 is a production product with warranted PC2-10000 performance. We ALSO reached DDR2-1300 and DDR2-1315 several months ago, with OCZ and Corsair, but neither product wass rated or warranted at PC2-10000.

    I have no doubt the Buffalo PC2-10000 is likely a good product. It is just we have neither seen or received for testing Buffalo PC2-10000 - we have only seen press announcements.
  • VooDooAddict - Wednesday, January 31, 2007 - link

    I'd like you to also show a zero based benchmark graph. I understand that you mention it in the article ... but too many people will just look at the graphs. Budget focused people also should see how little going down to 667 or even 533 effects the performance (I try to steer people to 800 just for a little more future proofing of their memory investment).

    I'm sick of people requesting this absurdly expensive RAM. I've got not problem people requesting the RAM for over clocking, the good looking cooler mods, or the brand name... but people are still requesting this stuff because they expect much better performance.

    I can make my own Zero based graph based on your numbers to show people ... but I'm much rather direct them to the original source.
  • Wesley Fink - Wednesday, January 31, 2007 - link

    The explanation is bold and tells readers why we show a limited range. It is difficult enough to pick out memory variations in a reduced range chart, and it would be almost impossible in a zero-based chart. We also clearly state results on a zero-based chart would show little variation in performance at different speeds.

    In the conclusion I was also very clear:

    "There is also the reality that Core 2 Duo and AM2 really don't need the highest memory speeds to perform best. What they need is low latency DDR2-800 or possibly 4-4-3 DDR2-1067 to get the best performance possible. The unfortunate reality that we see again and again in memory tests is that the super high memory speeds are great for bragging rights and flexible overclocking, but they really don't do much for increasing actual real world performance on either the C2D or AM2 platforms.

    Memory companies seem obsessed right now with higher and higher DDR2 memory speeds... We wish memory companies would become just as obsessed with producing a moderately priced 2 GB DDR2-800 kit that can perform day in and day out at 3-3-3 timings. It would be a bonus if it also overclocked to DDR2-1067 with 4-4-4 timings. With Vista performing best with 2GB of memory many will be upgrading memory as they move to the new OS. Whoever finally produces a reasonably-priced low latency DDR2-800 2GB kit will sell all they can produce."

    We are reviewing super high-end memory that is a good choice for some buyers, like overclocking enthusiasts, but they are a waste of money for the average buyer. We definitely agree once you get above 800 on C2D or AM2 there is very little gain in performance. Your money is better spent on a faster processor or an upgraded video card.
  • Live - Thursday, February 1, 2007 - link

    If there is no real world difference then why do you state in your buying guides that it is important to keep a 1:1 ratio?

    From the January 2007 Buyer's Guide: Midrange Menagerie

    Using a 1:1 memory:bus ratio (which is typically optimal for overclocking)

    This is not the only example. You seem to do this in all your memory reviews I have read lately as well. Granted they have been of high end memory and it seems unreasonable to spend that much on memory if you weren’t looking for the absolute maximum speeds. I still don’t understand tough why a 1:1 ratio is good for overclocking. It would seems to me that by lowering your memory ratio you could reach higher CPU overclocks cheaper which is what really matters, no? I mean most overclock as a way to save money not get the WR in superPI.

    The thing is for us that don't work with this everyday it’s hard to keep up and not fall for the aggressive marketing. I would appreciate it if you could devote a little more time to steer us right without breaking the bank. I know it’s probably not as fun but it would be much appreciated by us readers.
  • Neosis - Sunday, February 4, 2007 - link

    I think additional latencies shall arise at chipset level. Generally following stages take place while requesting data from memory:
    1- Data Request from CPU thru. the FSB
    2- Chipset transfer the request to memory from FSB
    3- Memory responds to the request
    4- Chipset then trasfer the request from the memory thru. FSB
    5- Finally the requested data travels across the FSB to the CPU

    In stage two and four, running the memory asynchronous to the FSB will increase latency. Since conroe has short pipeline like Amd, memory latency is more important than the memory bandwidth.
  • tayhimself - Wednesday, January 31, 2007 - link

    Sorry but that is a piss poor excuse. Its like published scientific studies saying, "we use this statistical analysis because its the only one that shows a significant difference". Who the hell would buy drugs based on that premise. Piss poor AT!! Reply
  • thudo - Wednesday, January 31, 2007 - link

    Conroe E6700 @ 3.66Ghz (1.53V) || Scythe Mine CPU Cooler + ArcticSilver5 Thermal Paste || OCZ 2gb PC8000 DC EL GEEK RAM || Asus P5W DH Mobo (1301 Bios) || EVGA 8800GTX ACS3 Cooling Edition (659/1013) || 2x10k Rpm WD SATA2 Raptor HDDs || Thermaltake Armour Full Tower w/side 250mm Mobo Case Fan || OCZ GamerX 700W PSU || WinXP+ SP2 + DX9c + All Updates || Latest Nvidia Forceware (97.x) || 3dmark2006 Score: 12,426 || SiSandra Int Buff'd iSSE2 : 7561 MB/s // Float Buff'd iSSE2 : 7562 MB/s

    Still surprised my box beats out the latest ram with the Overclock. Can only imagine having the new ram overclocked on the beat! :O

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