First Look: AM2 DDR2 vs. 939 DDR Performance

by Wesley Fink on 4/17/2006 12:05 AM EST
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  • phial - Thursday, July 05, 2007 - link

    "Comments are often made that any evaluation of AM2 should include overclocking. Those theorists argue that the faster processor clock will move AM2 to the higher "bus" speeds that make for better efficiencies of the DDR2 memory controller - or something along those lines."

    OK who hired this guy? He knows NOT what he speaks of. Its apparent through the entire review.
    Reply
  • phial - Wednesday, July 04, 2007 - link

    "This will likely shift to patterns similar to those seen in bandwidth positioning as the AM2 memory controller is further refined and game patches make better use of AM2 capabilities."

    Wow... and your posting hardware reviews on a high traffic website.. amazing...
    Reply
  • Zebo - Tuesday, April 18, 2006 - link

    I get everest of 42ns 2-2-2 @ 200 with FX60 speeds on DFI NF4. I get 36ns when cranking up to 250mhz 2-2-2. And that reminds me - I guess you did'nt want to embarres AMD's new chip too much by putting old, supported, DDR 550 @ 2-2-2 in there huh?

    What a dog this change is.
    Reply
  • Wesley Fink - Wednesday, April 19, 2006 - link

    Actually our Beta motherboard and CPU were not 100% stable at 275. Also I don't have any memory that will do DDR550 (275 clock speed) at 2-2-2. Perhaps you mean another speed or other timings.

    Our Crucial 2GB kit can do DDR500 at 3-2-3 timings, but our DDR2-800 memory is also capable of doing 3-2-3 at some speeds if the beta motherboard had supported those timings. That's the reason we compared 3-3-3 500, which should be very very close to each memory's top performance and a fair comparison.

    Our latency testing was at a slower speed than your FX60, which is why you got lower latency numbers. We did, however, set both the DDR and DDR2 platforms to the exact same speed and ratios for all the benchmarking. The results comparison was as fair as we could make it.
    Reply
  • spinportal - Tuesday, April 18, 2006 - link

    Let's see.. the 1GB PC-4400 DDR-550 kit is roughly 200$US for 2.5-3-3 timing. The DDR2-667 PC-5300 1GB kit is ~180$US for 3-3-3 timing for use to OC to DDR2-833. Unless I'm missing something, I don't understand your beef about spending $20 more for equal performance and using more juice. Reply
  • puffpio - Monday, April 17, 2006 - link

    I can see gaming benchmarks being VERY graphics and cpu calculation intensive...
    but in terms of the bus between the cpu and main memory..i dont see it as that intentive

    I wonder if a multitasking benchmark w/ lots of datasets would show off the increased bandwidth? (giant spreadsheets, databases, image processing, video encoding, etc etc)
    Reply
  • shady28 - Tuesday, April 18, 2006 - link


    "Real world" single user and light multitasking apps aren't going to use up the bandwidth. A heavy duty multitasking environment is what's needed to really test the benefits of dual core + DDR2. The thing is, this doesn't really describe what most PCs spend 99% of their time doing.

    That said, Conroe does look promising, and I'm interested to see what AMD can come up with to counter it. The initial performance advantages, according to *Intel* benchmarks, are pretty significant. Hopefully AM2 is just laying the groundwork for faster processors from AMD. Still, I can't help but think the performance boosts we've been getting since about 2001 (3.06Ghz P4 HT) are marginal, and that this is yet another marginal boost.
    Reply
  • NullSubroutine - Monday, April 17, 2006 - link

    I am still convinced that the transition from DDR to DDR2 is primiarily because it unifies the memory production industry, lowers power for server and mobile areans, increases memory bandwidth for upcoming memory hog (ie vista), and servers as a platform of increased memory capability. As for the last point I think most of us believe that quad core CPU's may use more memory bandwidth and the original DDR may act as a bottleneck for the system. I also think it is clear that memory bandwidth is not a bottleneck for AMD, but I applaud them taking care of a potential bottleneck before it exists, unlike Intel who has continuelly bottlenecked their CPUs by insuffient memory bandwidth. Reply
  • NullSubroutine - Monday, April 17, 2006 - link

    quote:

    (ie vista), and servers


    should say serves obviously.
    Reply
  • eRacer - Sunday, April 16, 2006 - link

    Was the DDR2 using a 2T command rate and was the DDR-400 tested using 1T? Is there an option to change the command rate on the AM2 motherboards? I believe at least some Pentium DDR2 motherboards with NVIDIA chipsets have the option to use a 1T command rate.

    I've seen some Sandra 2005 standard memory tests gain 500MB/s or more just by using 1T instead of 2T. A gain like that would allow DDR2-533 1T to score higher than DDR2-800 2T in the Sandra 2005 standard memory test. If DDR2-800 could use a 1T command rate the performance gain in the non-synthetic benchmarks might be a few percent higher on average. While that doesn't sound like much it would be roughly double the DDR2-800 performance advantage over DDR-400 in this review.
    Reply
  • Ecmaster76 - Saturday, April 15, 2006 - link

    Wouldn't it be the best way to suck up bandwidth? We already knew a single core had enough bandwidth from the 754-939 transition.

    I guess its not that big a deal now because the parts aren't even for sale. But as long as you do tsome multitasking articles on the final hardware I'll be happy.
    Reply
  • IntelUser2000 - Saturday, April 15, 2006 - link

    So... the conclusion is that DDR2-800 is needed to outperform DDR400. DDR2-667 is slower than DDR400. The Inquirer is correct, contrary to some other opinions. Reply
  • Wesley Fink - Saturday, April 15, 2006 - link

    Latency and Bandwidth of DDR2-533 are about the same as DDR400, and DDR2-667 and DDR2-800 are both faster. Games and Applications SHOULD be faster on both DDR2-667 and DDR2-800. However, given current aopplications and the AM2 memory controller, the applications and games are about the same at DDR2-667 - and DDR2-800 is faster as you state.

    This is likely the result of the late pre-release AM2 memory controller and applications/games themselves not being optimized for DDR2 on AM2. Both will likely be fixed very quickly, and actual performance of DDR2-533 should then be roughly on par with DDR400 - with 667 and 800 both faster.
    Reply
  • psychobriggsy - Saturday, April 15, 2006 - link

    If 2.5GHz was a 40% overclock, then the AM2 processor tested must have been running at 1.8GHz (9x200, i.e., it was also unlocked for you to get 10x250).

    It's not surprising that a 1.8GHz K8 processor wouldn't benefit from DDR2 much - indeed I expect that most of the application improvements were just from the slightly reduced latency at DDR2-800 rather than actually having more bandwidth available.

    I wonder what a stock 2.8GHz AM2 X2 with DDR2-800 would get against a stock 2.8GHz 939 X2 with DDR-400? No, I don't think it will be a miracle, but just possibly it will start actually needing the extra bandwidth available, which could lead to a greater gap between the two platforms.

    I guess we'll find out in under 2 months.
    Reply
  • Wesley Fink - Saturday, April 15, 2006 - link

    The AM2 processor was NOT a 1.8GHz x2. I stated the CPU could overclock 40% at stock speeds, but the 10x250 is not that 40% overclcok. We chose that ratio because it is a clock speed our DDR2 memory could handle and it was also a speed doable on 939 for a reasonable comparison. We actually had two AM2 processors this round, a top-line AM2 and a more mainstream processor. We looked at performance from both, and it was the same at the same processor speed. The DDR2 memory controller reports as Rev. F.

    As for the question about manufacture date, we are providing as little information about these pre-release processors and motherboards as possible to protect our sources. We have several sources who work with us to bring you the latest news before anyone else, and we don't want to compromise those relationships. Therefore we are not providing any information that might make it easier for AMD and others to trace our sources.

    We can assure you these are the latest Rev. AM2 shipped to AMD partners in early April as we have evaluated 4 versions since mid-January. This is also the first rev. to fully support DDR2-800.
    Reply
  • Viditor - Saturday, April 15, 2006 - link

    quote:

    we are providing as little information about these pre-release processors and motherboards as possible to protect our sources

    Fair enough...had to ask.
    Reply
  • Viditor - Saturday, April 15, 2006 - link

    My concern is that while Anand is just receiving the part, if it's off of a recent production run then AMD will have some problems with the launch. Usually you need a full turn's worth of product in inventory for a launch...if they are just turning out final product now, then my guess is there will be shortages come July. Of course since they have doubled their capacity recently it will be much less, but still...it doesn't bode well.

    Anand, could you confirm the manufacture date of the chip you tested for us please?
    Reply
  • Viditor - Saturday, April 15, 2006 - link

    Apologies...I should have addressed the previous question to Wesley (sorry mate).
    I know that APM allows AMD to change anything (even down to individual dice on the wafer) at any point in the process, but my concern is inventory levels here. If you could please confirm the production date on the chip you used for testing, it would help me significantly with my analysis of the upcoming launch.

    Cheers!
    Reply
  • Jynx980 - Saturday, April 15, 2006 - link

    Typo on page 3, paragraph 5:
    quote:

    we DDR timings we have tested
    Reply
  • Wesley Fink - Saturday, April 15, 2006 - link

    The extra "we" has been removed. Reply
  • peternelson - Saturday, April 15, 2006 - link


    I notice all your tests were performed in 32 bit mode.

    This cpu can handle 64 bit instructions.

    While 64 bit registers (and more of them) allows faster data manipulations, that advantage is traditionally offset by the need for bigger wordsize of instructions.

    So if the memory reading of the instructions is more memory-hungry that could be more use for this extra memory bandwidth.

    Therefore I suspect IN 64 BIT MODE, there could be more advantage on a fast DDR2 than on a bandwidth-limited DDR system.

    How to test this? Well you could run some 64 bit Windows and BENCHMARK FAR CRY in 64 bits version as it is available as 32 and 64 bit.

    See if running in 64 bit with this new ddr2 memory negates the disadvantage of limited bandwidth for instruction feeding?

    If so this would be increasingly an advantage in future as more people move to 64 bit OS, including at Vista-time.
    Reply
  • smitty3268 - Saturday, April 15, 2006 - link

    The larger instruction size is barely an issue. The real difference is that all pointers are doubles in size from 32 to 64 bits. This can lead to a significantly lower number of variables stored on the cache, which can lead to increased bandwidth usage. Reply
  • AnandThenMan - Saturday, April 15, 2006 - link

    I agree with what you are saying. In 64 bit mode, that A64 *should* benefit from the increased DDR bandwidth.

    The problem is, the 64 bit version of Farcry was basically a scam and offered no performance or visual increases solely because it was a 64 bit optimized game. If I remember correctly, the extra visual effects in the 64 bit version were basicially enabled if run in 64 bit mode, but had little or nothing to do with actually being optimized for the A64 in 64 bit mode.
    Reply
  • peternelson - Saturday, April 15, 2006 - link


    I see your point too.

    Yes some additional features could have been done on 32 bit version but were restricted to 64 bit platforms. But surely the compiled binary was actually a 64 bit binary even if not optimised much? In which case it would still be interesting to compare.

    32 bit DDR versus 64 bit DDR and versus 32 bit DDR2 and versus 64 bit DDR2.

    My hypothesis is that the speedup (even if small) from using the 64 bit binary over the 32 will be greater on AM2 DDR2 than the same test on 939 DDR.

    I agree that Far Cry was not the best example, but you may know of other good benchmarks or games which are tuned for this.

    eg the same four tests of PRIME95 (www.mersenneforum.org) which is available in 32 and 64 bit. The Trial factoring test benchmark shows a good speedup in 64 over 32 bit operations. But then that doesn't use main memory much as it is highly optimised to work inside the L1/L2 cache. There must be other suitable tests though to compare 32 and 64 bit on some memory intensive task with binaries optimised for each architecture.
    Reply
  • IntelUser2000 - Saturday, April 15, 2006 - link

    quote:

    My hypothesis is that the speedup (even if small) from using the 64 bit binary over the 32 will be greater on AM2 DDR2 than the same test on 939 DDR.


    Right, the hypothesis for higher clock speed giving better increases were similar, however it gave less increases.


    Wesley, there is another typo. On this page: http://www.anandtech.com/cpuchipsets/showdoc.aspx?...">http://www.anandtech.com/cpuchipsets/showdoc.aspx?...

    DDR400 to DDR2-800 performance increase in CoD2 is said to be 10.6%. That is not correct. DDR400 to DDR2-533 is 10.6%, but DDR400 to DDR2-800 is only 6.7%. Check your calculation numbers please.
    Reply
  • Wesley Fink - Saturday, April 15, 2006 - link

    The calculation has been corrected. Thank you for catching this and bringing it to our attention. Reply
  • peternelson - Saturday, April 15, 2006 - link

    You should not claim AMD's on-processor memory controller is UNIQUE".

    Unique means nobody else does it and it is a unique feature of AMD.

    THAT is incorrect.

    Although Intel don't do it, there are other chips that have on-chip DDR or DDR2 controllers including Clearspeed. I can even put a ddr or ddr2 controller (or several) into my own chip designs in a Xilinx FPGA because Xilinx license the design free for use in their chips.
    Reply
  • Griswold - Saturday, April 15, 2006 - link

    Pretty unique in the x86 world, isnt it? Reply
  • peternelson - Saturday, April 15, 2006 - link


    No, actually it isn't. That was precisely my point.

    Transmeta Efficeon and VIA C7 can both have on die memory controllers too.

    They run x86 instructions quite happily.

    Don't get me wrong, it's a good idea, it's just not UNIQUE any more.
    Reply
  • Wesley Fink - Saturday, April 15, 2006 - link

    Transmeta and the VIA C7 aren't really AM2 and Conroe competitors in most situations. However, I can conceive some applications where they might be. To be more precise I will try to use another word to describe the on-processor memory controller in the future.

    Do you work for VIA or Transmeta?
    Reply
  • peternelson - Saturday, April 15, 2006 - link

    No I don't work for VIA or Transmeta but I do work in the IT Industry ;-)

    Efficeon chips were used in Orion Multisystems DT-12 and DS-96 cluster in a box computers and some notebooks.

    Whilst they have low power, they do lack performance for some applications compared to the latest chips. But using VLIW based code-morphing they do indeed run x86 code.

    Just call it a "good idea" rather than "unique" ;-)
    Reply
  • Bladen - Friday, April 14, 2006 - link

    Although DDR2 667 at 3-3-3 doesn't seem that common, all I can find is DDR2 667 4-4-4 or 5-5-5. Here in Australia anyway.

    Maybe when AM2 is released a rehash article featuring the higher latencies is in order.
    Reply
  • Gary Key - Saturday, April 15, 2006 - link

    quote:

    Although DDR2 667 at 3-3-3 doesn't seem that common, all I can find is DDR2 667 4-4-4 or 5-5-5. Here in Australia anyway.


    In our recent experiences with Infineon based DDR2-667 modules rated at 4-4-4, the majority of these modules will run at DDR2-667 with 3-3-3 settings with a voltage setting around 2.2V. Your mileage will vary based upon supplier but going with one of the more performance oriented providers will usually result in the better timings.

    We fully expect a wave of higher performance DDR2 modules to be launched in conjunction with the AM2 product. The majority of these new modules settling in around the DDR2-667 and DDR2-800 levels or above as we recently witnessed in our DDR2-1000 article -http://www.anandtech.com/memory/showdoc.aspx?i=273...">DDR2-1000 goes Higher.....
    Reply
  • AnandThenMan - Friday, April 14, 2006 - link

    quote:

    This may change in the future, but for now the move to AM2 and DDR2 memory looks like it will yield far too little in performance improvements to keep AMD competitive in the upcoming marketplace.


    It will be interesting to come back to this statement after AM2 and Conroe are out in the wild to see how accurate it was.

    Interesting article, but nothing very surprising to me. The Athlon64 core is pretty much at its computational limit at a given clock, feeding it with more memory bandwidth does little. Which means that early adopters of the AM2 platform will get 939 performance with an updgrade path, which is not too shabby.

    Conroe better live up to expectations though...
    Reply
  • Wesley Fink - Saturday, April 15, 2006 - link

    It would be a very pleasant surprise if AMD has us all in the dark and launches a Conroe competitive part or a Conroe-killer. Competition is good for buyers, especially when performance is very close. The close performance results in lower prices, as we are now seeing in the ATI/nVidia video cards from the most recent generation.

    However, we have to evaluate things with the best information we have available on time to Fab, launch dates, and the available revs that have been provided to AMD partners to design their companion products for the AM2 launch. There is always room for an unexpected surprise, but it looks less likely the closer we get to 6/6/06.
    Reply
  • Viditor - Saturday, April 15, 2006 - link

    I have no doubt that AM2 is a very weak upgrade...management at AMD said as much in their recent conference call.
    The only critique I have would be of the line
    quote:

    the move to AM2 and DDR2 memory looks like it will yield far too little in performance improvements to keep AMD competitive in the upcoming marketplace

    You should have added the word "desktop" before marketplace as the server marketplace should still be solidly AMD, and we have yet to see what will happen in the mobile space...JMHO
    Reply
  • Wesley Fink - Saturday, April 15, 2006 - link

    A very fair comment. I added the "desktop" qualifier since it makes sense. Reply

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