DDR3 vs. DDR2

by Wesley Fink on May 15, 2007 2:40 PM EST
Conclusion

The purpose of this comparison of DDR3 and DDR2 was to determine whether DDR3 really brought any better performance to the Core 2 platform. However, the test was designed so that any performance improvements that were brought by the new P35 (Bearlake) chipset would be captured and could be isolated. P35 supports either DDR2 or DDR3, and we found no real difference in current performance of DDR2 and DDR3 on the P35 platform. Both were equally faster than the same DDR2 on the P965 chipset.

That means the real performance surprise in these tests is that the revised memory controller in the Bearlake chipset improves buffered memory bandwidth by 16% to 18%, with a real-world improvement in gaming and application performance of 2 to 5%. This is a pretty impressive improvement for a memory controller update. To repeat an old saying please remember that memory is just one small part of the system, so a 2% to 5% increase in gaming from the memory controller alone means the P35 memory controller is significantly improved over the P965 chipset.

DDR3 at introduction is saddled with pretty dismal memory timings. As you can see in our test bed chart, SPD timings are 6-6-6-15 at DDR3-800, 7-7-7-20 at DDR3-1066 and 9-9-9-25 at DDR3-1333. Despite the slower timings DDR3 runs at higher speeds than any DDR2 we have tested, and we will have official JEDEC timings for DDR3 to 1600 with the current JEDEC standard, and possibly ever faster with any future JEDEC update.

Even at slow timings, DDR3 shows a great deal of promise. It is as fast as very fast DDR2 on the P965, but it can't match the same DDR2 memory performance on the P35. DDR3 can run at higher speeds than DDR2 and as faster memory timings inevitably appear DDR3 will be the right choice for computer enthusiasts looking for the best performance. While we can't prove better latency or significantly better performance with the slow timings of launch DDR3, the evidence is all there in these tests. DDR3 will get faster in speed and will provide the best performance in the long term.

That brings up the more difficult question: what to buy today? That is a much more complicated question. If you are looking for a new system, definitely choose the new P35 chipset over the P965, as it is a better memory performer. At launch we are told DDR3 will be much more expensive than DDR2. Prices are expected to be about $480 for a 2GB DDR3 kit. At that lofty price it is difficult to recommend DDR3 over DDR2, when DDR2 performs just the same on the P35 chipset and decent 2GB kits can be had for under $150 now.

Two conditions would shift the recommendation to DDR3 instead. When DDR3 prices come close to DDR2 then buy DDR3 instead. More significantly, when DDR3 becomes available at higher speeds and/or faster timings then definitely choose DDR3 if you are looking for performance - even if the price is higher.

We asked many memory vendors when they thought price parity and fast DDR3 timings might be available. The more skeptical said not until late 2008, while the more optimistic felt it would happen by the end of 2007. Until either or both events happens there is no compelling reason to buy DDR3. However, there is no doubt at all that DDR3 is in your future as the top-performing memory you can buy. Some will also buy it because it is the future and they can likely carry their DDR3 supporting board a little further into the future.

AMD's launch of their Phenom processors will also be something to consider for it's potential impact on DDR3 adoption. Phenom will initially launch with DDR2 only. If AMD can regain the performance crown, the shift to DDR3 may be further delayed, just like what happened with the DDR to DDR2 shift.

The winner for now is the P35 chipset, whether you feed it DDR2 with fast timings or higher speed DDR3. The 1333 bus speed introduced by P35 is also a winner - at least in terms of overclocking. As stated in the review, almost every Core 2 Duo and Core 2 Quad we tried in the P35 ASUS P5K and P5K3 ran at 1333 FSB at the default multiplier and default voltage. The only processors that required any voltage increase were the top line Core 2 Extreme processors. This free 25% overclock, which still allows everything else in the system to run at default values, is exciting. It is so exciting we have to wonder how long Intel will allow this in the marketplace.

DDR3 may not be in your buying plan today, but it will certainly be there in the future. As DDR3 prices drop and/or timings improve, it will be the performance choice. For today, the best performance choice is either today's DDR2 or tomorrow's DDR3 on the P35 chipset instead.

Number Crunching and Gaming
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  • 13Gigatons - Wednesday, May 16, 2007 - link

    Suddenly it doesn't seem like a bad decision on AMD's part to hold off on their move to AM3 and DDR3 until 2008/2009. I really don't get why we need to change the memory technology so fast, with DDR2 finally dropping in price so fast.

    I'd rather have 4GB of DDR2 then 1GB of DDR3.
  • Sunrise089 - Wednesday, May 16, 2007 - link

    Actually, a 2%-5% performance jump is very impressive from anything other than a CPU or GPU. Running a Raptor versus a 7200RPM drive, or a high-end motherboard versus a budget model, or a add-on sound card versus onboard audio all are choices many people make without any huge double digit performance gains in most applications.

    Thats said, the 2%-5% gain isn't from the memory standard (did you even read the article?) but from the new chipset. So these numbers have absolutely no bearing on AMD's choices.
  • Googer - Tuesday, May 15, 2007 - link

    If you wanted to test bandwidth effects, why use a processor that is not very bandwidth dependant? Instead a bandwidth hungry LGA-775 Prescott should have been one the CPU's used in these DDR3 benchmarks. I'd like to see this article updated with a dual core netburst processor added.
  • TA152H - Wednesday, May 16, 2007 - link

    Are Prescotts even relevant anymore though? I mean, how many people are going to be perspecacious enough to buy a P35 based motherboard, and care about memory performance, and then go out and buy something as foul as a Prescott? It might make for an interesting data point, but it's a very little practical value.
  • vailr - Tuesday, May 15, 2007 - link

    Please include, in your forthcoming P35 board review: enabling SATA AHCI mode. Still remains puzzling, especially when a board uses a non-Raid Intel chipset, such as the ICH8. Gigabyte says on their web site, that on the GAS-965P-DS3, that AHCI should only be enabled when running Vista. Several other questions remain, such as: AHCI seems to work fine under WinXP when using the latest 1.17.17 JMicron drivers (single HD connected to a JMicron SATA port). Connecting the same HD to an Intel port, and AHCI won't work. Intel's offical AHCI drivers only seem to install when a Raid array is present.
    In summary: please include comments on any differences and/or improvements in AHCI support between the 965 v. P35 chipsets.
  • Comdrpopnfresh - Tuesday, May 15, 2007 - link

    There was an article a few months ago saying that speed increases on ddr2 didn't really matter, the architecture for the memory was old enough that there was a decline in performance advantage as speeds increase. If ddr3 is basically the same as ddr2, wouldn't the same be expected? Does anyone have any idea when the timings will come down? The voltage is nothing to gawk at- it's the reason for the increased speed. On the gate level, the less space between high and low, he faster a gate can transition. I'm most interested to see ddr3 performance and bandwidth numbers w/ amd processors.
  • R3MF - Tuesday, May 15, 2007 - link

    i currently have
    an X2 system with PC3200 dual channel
    and a C2D system with PC6400 dual channel

    i definitely see a quad core 3.2GHz chip running PC12800 in my future.

    hooray for technology!
  • DeepThought86 - Tuesday, May 15, 2007 - link

    I wonder how long before Intel gets impatient and starts not-so-gently shoving DDR3 down people's throats long before the price or performance justify it?

    "Oh look, our chipsets for Nehalem don't support DDR2, woops you'll have to dump your DDR2 and get this spiffy new stuff. Look, it went from 2 to 3, it must be better!"
  • theprodigalrebel - Wednesday, May 16, 2007 - link

    I remember reading an article somewhere where the interviewer asked an AMD person about Intel pushing for DDR3. The guy admitted that DDR3 is the way of the future - though not ready/relevant today - and only a company like Intel can drive that change.

    In his words, AMD's move to DDR2 came at the right time - in terms of price and advances in bandwidth/latency where DDR2 finally defeated the best DDR kits. He admitted that the move wouldn't have been possible unless Intel had moved the market in that direction over the past year or so.

    Intel has driven changes from AGP to PCI-Express, IDE to SATA and DDR to DDR2. It seems forced at first - and it probably is - but you don't HAVE to be an early adopter. You had the 925 chipset introducing DDR2 and 915 boards supporting DDR. That is exactly what is happening here.
  • TA152H - Tuesday, May 15, 2007 - link

    You need for Intel to push stuff down people's throats, or you'd never get these changes. No other company is in a position to, it's like IBM used to be almost 20 years ago.

    The price of the memory will go down as production goes up, which of course is driven by demand, which of course has to be driven by Intel. If not Intel, then who?

    By offering a chipset that offers both, they are slowly starting the transition and the prices should get closer. At some point, supporting DDR2 is just a waste of chipset space and is costing people money that have no intention of ever using it, so you get rid of it. At that point it might cost a little more still, but that's the price you pay for transitioning to a better technology, and making that technology cost effective. I think they're extremely important to the industry for exactly that reason, not a malicious force.

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