First Look: AM2 DDR2 vs. 939 DDR Performance
by Wesley Fink on April 17, 2006 12:05 AM EST- Posted in
- CPUs
Final Words
When the article OCZ EL PC2-8000 XTC: Low Latency PLUS DDR2-1100 was posted a couple of weeks ago, the potential of this incredibly fast DDR2 memory on the upcoming AM2 platform was clear. What was not expected was that the opportunity to run the DDR2-1000 memory through its paces on an AM2 was only a couple of weeks away. After looking more closely at DDR2 memory performance on the 4th spin of the AM2 processor it is clear AMD will definitely be able to launch AM2 with the expectation of better performance than the Socket 939 it replaces. This avoids one of the huge pratfalls that plagued Intel in their move to DDR2.
However, the memory bandwidth increases of up to 30% on AM2 and the Latency improvements of 12 to 16% compared to the fastest DDR memory on socket 939 do not yield much in real-world performance. The real-world performance increase for AM2 compared to Socket 939 will likely be very small - in the range of no increase to about 7%, depending on the application.
In normal times this would be great news! In times where previews of Intel's new Conroe architecture show solid 20%+ improvements in performance compared to AMD Socket 939, these smaller AM2 increases are reason for concern. It certainly appears that unless some unforeseen miracle happens, the move from Socket 939 DDR to AM2 DDR2 just can't generate anywhere near the performance improvement AMD really needs to combat Intel's Conroe. This article evaluated memory and gaming performance, but you can see comparisons of General Performance, multimedia and encoding in the companion article AMD Socket-AM2 Performance Preview.
Not all is gloom in the AMD camp, however, as there are certainly bright spots. AM2 IS faster than Socket 939, with even more possible DDR2 bandwidth for the future. Unfortunately, unless AMD makes revisions to the core and/or adds more cache with the 65nm die-shrink there is not much improvement from the move to AM2. The extra bandwidth and lower latency just don't translate into meaningful performance improvements with today's applications.
There are also a few general observations about using DDR2 with the new upcoming AM2. Using fast, top-line memory DDR2-533 is roughly equivalent in bandwidth to fast DDR400 memory. That observation should also hold with mainstream memory where DDR400 3-3-3 should perform about like DDR2-533 4-4-4. Most memory manufacturers will also be producing fast high-end DDR2-800 and more mainstream DDR2-667 and DDR2-800 parts for launch with AM2, so there will likely be many more memory choices when AM2 launches.
Last, the move to a unified memory specification with Intel will likely be a good development for those looking to buy new DDR2 memory. With AMD and Intel both using DDR2 there will likely be more innovation in the DDR2 market, more choices, and even better prices. Add to that the expectation that both AM2 and Conroe will launch with official DDR2-800 support and faster DDR2 memory should be much easier to find and afford in the near future.
It appears AMD will succeed in launching a faster on-processor DDR2 memory controller. The latest AM2 pre-release samples are showing significant improvements over Socket 939 DDR in both memory bandwidth and latency. Unfortunately, the current AMD architecture running current applications and games doesn't appear to need the additional bandwidth or reduced latency. 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 desktop marketplace.
When the article OCZ EL PC2-8000 XTC: Low Latency PLUS DDR2-1100 was posted a couple of weeks ago, the potential of this incredibly fast DDR2 memory on the upcoming AM2 platform was clear. What was not expected was that the opportunity to run the DDR2-1000 memory through its paces on an AM2 was only a couple of weeks away. After looking more closely at DDR2 memory performance on the 4th spin of the AM2 processor it is clear AMD will definitely be able to launch AM2 with the expectation of better performance than the Socket 939 it replaces. This avoids one of the huge pratfalls that plagued Intel in their move to DDR2.
However, the memory bandwidth increases of up to 30% on AM2 and the Latency improvements of 12 to 16% compared to the fastest DDR memory on socket 939 do not yield much in real-world performance. The real-world performance increase for AM2 compared to Socket 939 will likely be very small - in the range of no increase to about 7%, depending on the application.
In normal times this would be great news! In times where previews of Intel's new Conroe architecture show solid 20%+ improvements in performance compared to AMD Socket 939, these smaller AM2 increases are reason for concern. It certainly appears that unless some unforeseen miracle happens, the move from Socket 939 DDR to AM2 DDR2 just can't generate anywhere near the performance improvement AMD really needs to combat Intel's Conroe. This article evaluated memory and gaming performance, but you can see comparisons of General Performance, multimedia and encoding in the companion article AMD Socket-AM2 Performance Preview.
Not all is gloom in the AMD camp, however, as there are certainly bright spots. AM2 IS faster than Socket 939, with even more possible DDR2 bandwidth for the future. Unfortunately, unless AMD makes revisions to the core and/or adds more cache with the 65nm die-shrink there is not much improvement from the move to AM2. The extra bandwidth and lower latency just don't translate into meaningful performance improvements with today's applications.
There are also a few general observations about using DDR2 with the new upcoming AM2. Using fast, top-line memory DDR2-533 is roughly equivalent in bandwidth to fast DDR400 memory. That observation should also hold with mainstream memory where DDR400 3-3-3 should perform about like DDR2-533 4-4-4. Most memory manufacturers will also be producing fast high-end DDR2-800 and more mainstream DDR2-667 and DDR2-800 parts for launch with AM2, so there will likely be many more memory choices when AM2 launches.
Last, the move to a unified memory specification with Intel will likely be a good development for those looking to buy new DDR2 memory. With AMD and Intel both using DDR2 there will likely be more innovation in the DDR2 market, more choices, and even better prices. Add to that the expectation that both AM2 and Conroe will launch with official DDR2-800 support and faster DDR2 memory should be much easier to find and afford in the near future.
It appears AMD will succeed in launching a faster on-processor DDR2 memory controller. The latest AM2 pre-release samples are showing significant improvements over Socket 939 DDR in both memory bandwidth and latency. Unfortunately, the current AMD architecture running current applications and games doesn't appear to need the additional bandwidth or reduced latency. 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 desktop marketplace.
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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" ;-)
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.
Gary Key - Saturday, April 15, 2006 - link
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.....
AnandThenMan - Friday, April 14, 2006 - link
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...
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.
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
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
Wesley Fink - Saturday, April 15, 2006 - link
A very fair comment. I added the "desktop" qualifier since it makes sense.