Conclusion
While DDR2 Memory does not exhibit the same bandwidth or performance on the AM2 and Conroe platforms, they do perform at the same timings and voltages when going from one platform to another. This was clearly demonstrated in benchmarking tests performed on AM2 and Conroe platforms. This means readers can examine test results performed on a Core 2 Duo test bed with XYZ memory, and reasonably expect that XYZ memory to perform at the same speeds and the same memory timings and voltages on an AM2 platform - provided those settings are available.
There are always the variations in chipset and BIOS that can cause problems with a memory on one brand/model of motherboard and no problems on another brand/model, but that is also true even if you are planning to use the DDR2 on the same type of platform. We have sometimes seen where a brand of memory runs very well on an MSI platform, for example, but where it would not run at all on a DFI platform using the same chipset and CPU. Those types of compatibility issues will always happen, but in general if a memory tests well on Conroe it should do just as well on AM2.
This fact will make our memory testing much simpler, and we plan to perform all upcoming memory testing on the currently more flexible Core 2 Duo test platform. AM2 buyers can expect similar results with the same DDR2 memory on their AM2 motherboards.
A few conclusions about AM2 performance compared to Core 2 Duo performance are also inescapable in looking at our test results. First, Intel has done a remarkable job of concealing the issue of not having an on-processor memory controller. The intelligent look-ahead for memory works very well, and it makes the chipset-based Core 2 Duo memory controller appear to be as fast as the on-processor AM2 in many cases. This does not change the fact that the AM2 memory bandwidth is really greater than Core 2 Duo or the fact that AM2 scales better in memory, exhibiting a steeper slope in performance increase as memory speed increases than does Core 2 Duo. That just means as Memory Speed increases AM2 will benefit more and Intel will eventually need to move to an on-processor controller.
Probably the hardest conclusion for many will be the fact that increasing memory speed, increasing clock speed, and increasing CPU speed alone will not be enough for AM2 to catch up to Core 2 Duo in performance. The performance gap that remains when overclocking AM2 to 2.93GHz at 266 clock speed with DDR2-1067 is still huge. A die-shrink from 90 to 65nm and the additional cache that will allow will definitely help, but we are even skeptical there with Core 2 Duo already overclocking to 4GHz and beyond. No doubt AMD will find a solution, but it is now clear this will not be an easy fix for AMD.
The deep price cuts announced by AMD yesterday will definitely help. The new numbers indicate AM2 will be very competitive at the low end to low-mid of the processor food chain - a spot they have held in the past and where they have still managed to survive. The low end looks very competitive, and AMD is positioned close enough to mid-range in performance to keep Intel honest. There is no mistaking, however, that Intel Core 2 Duo owns the mid to high-end of the current processor market.
With this memory analysis, the memory playing field is hopefully a lot clearer for those shopping for DDR2 memory. Our next memory articles will compare memory performance of DDR2 on the Core 2 Duo Memory Test Bed. This began with the 6 high-performance memories and the 7 value memories tested in the Conroe Buyers Guide. It will continue with evaluations of the fastest memories available from both Corsair and OCZ.
While DDR2 Memory does not exhibit the same bandwidth or performance on the AM2 and Conroe platforms, they do perform at the same timings and voltages when going from one platform to another. This was clearly demonstrated in benchmarking tests performed on AM2 and Conroe platforms. This means readers can examine test results performed on a Core 2 Duo test bed with XYZ memory, and reasonably expect that XYZ memory to perform at the same speeds and the same memory timings and voltages on an AM2 platform - provided those settings are available.
There are always the variations in chipset and BIOS that can cause problems with a memory on one brand/model of motherboard and no problems on another brand/model, but that is also true even if you are planning to use the DDR2 on the same type of platform. We have sometimes seen where a brand of memory runs very well on an MSI platform, for example, but where it would not run at all on a DFI platform using the same chipset and CPU. Those types of compatibility issues will always happen, but in general if a memory tests well on Conroe it should do just as well on AM2.
This fact will make our memory testing much simpler, and we plan to perform all upcoming memory testing on the currently more flexible Core 2 Duo test platform. AM2 buyers can expect similar results with the same DDR2 memory on their AM2 motherboards.
A few conclusions about AM2 performance compared to Core 2 Duo performance are also inescapable in looking at our test results. First, Intel has done a remarkable job of concealing the issue of not having an on-processor memory controller. The intelligent look-ahead for memory works very well, and it makes the chipset-based Core 2 Duo memory controller appear to be as fast as the on-processor AM2 in many cases. This does not change the fact that the AM2 memory bandwidth is really greater than Core 2 Duo or the fact that AM2 scales better in memory, exhibiting a steeper slope in performance increase as memory speed increases than does Core 2 Duo. That just means as Memory Speed increases AM2 will benefit more and Intel will eventually need to move to an on-processor controller.
Probably the hardest conclusion for many will be the fact that increasing memory speed, increasing clock speed, and increasing CPU speed alone will not be enough for AM2 to catch up to Core 2 Duo in performance. The performance gap that remains when overclocking AM2 to 2.93GHz at 266 clock speed with DDR2-1067 is still huge. A die-shrink from 90 to 65nm and the additional cache that will allow will definitely help, but we are even skeptical there with Core 2 Duo already overclocking to 4GHz and beyond. No doubt AMD will find a solution, but it is now clear this will not be an easy fix for AMD.
The deep price cuts announced by AMD yesterday will definitely help. The new numbers indicate AM2 will be very competitive at the low end to low-mid of the processor food chain - a spot they have held in the past and where they have still managed to survive. The low end looks very competitive, and AMD is positioned close enough to mid-range in performance to keep Intel honest. There is no mistaking, however, that Intel Core 2 Duo owns the mid to high-end of the current processor market.
With this memory analysis, the memory playing field is hopefully a lot clearer for those shopping for DDR2 memory. Our next memory articles will compare memory performance of DDR2 on the Core 2 Duo Memory Test Bed. This began with the 6 high-performance memories and the 7 value memories tested in the Conroe Buyers Guide. It will continue with evaluations of the fastest memories available from both Corsair and OCZ.
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sld - Tuesday, July 25, 2006 - link
Yes I second the importance of a 32M run, because I want to know how Core 2 Duo does when the dataset does not fit into the L2 cache. The Intel fanboys at xtremesystems are annoying me with their whoops of glee over the 1M and 2M results.The performance difference in games and superpi is large enough to be termed anomalous, simply because superpi is a feel-happy benchmark.
Calin - Tuesday, July 25, 2006 - link
I've had the same issue on understanding the graphic - but I think it is much better now (top representing better performance, with the scale inverted)Anyway, great article!
As for the increases in cache helping AMD processors, I guess not - considering the small difference from 512k to 1M.
mattsaccount - Tuesday, July 25, 2006 - link
Never mind, I'm tired :)goinginstyle - Tuesday, July 25, 2006 - link
Page 7 is going to upset a lot of AMD fans.Page 9 index description needs to be "conclusion".
Great article and would love to see this comparison with the E6600 and E6300 CPUs against the competing AMD cpus. A lot of us will be buying these two processors and probably plain DDR2800.
OcHungry - Tuesday, July 25, 2006 - link
Can I ask you what memory timings you used?Since you have stated that memory speed does not affect conroe, would it be fair to assess that you used tightest timings for AM2?
If not: why?
About what page is going to make AMD users upset or hate the page, I totally disagree with you. You actually brought some lights to the whole scheme of things, unintentionally and unknowingly. You have helped to prove that Conroe will only be a mere 1 or 2% faster than AM2, which is not noticeable in real life situation. Conroe is only faster in Spi- But again, AMD beats Intel in memory bandwidth by a great margin. Memory bandwidth is much more important than SPI in terms of game and general cpu task(s). I will prove to everyone, that AMD is just as fast as conroe and post my reasoning in the cpu section, as soon as I have analyzed your benchmark data and made my calculations. But I need to know what memory timings you did use thu. A screenshot of timings would be great.
Again, thank you for this review that helped us open our eyes and see things in a better perspective.
Gary Key - Tuesday, July 25, 2006 - link
Wes replied earlier in the comments section but the settings are now posted on page 4 of the review.
goinginstyle - Tuesday, July 25, 2006 - link
Caluclations? I would like to see your benchmarks on actual hardware and not some scribbling on your Happy Meal napkin. I can caluclate that you are an idiot but really do not have the time to do it since I have a real life.
zsdersw - Tuesday, July 25, 2006 - link
1 or 2% faster? Please share with the rest of us what you're smoking.
Conroe is significantly faster on almost all fronts... in spite of having lower memory bandwidth.
Calin - Wednesday, July 26, 2006 - link
I suggest you to use a tractor and two trailers - one for persons and one for cargo. Even if you won't go faster than people with cars, you will have a huge bandwidth (persons and cargo bandwidth).If you buy your processor for bandwidth, choose whatever you want. If you buy it for speed, buy based on actual performance
bob661 - Tuesday, July 25, 2006 - link
I thought you didn't care about this stuff?