DDR3 vs. DDR2

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

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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  • vaystrem - Tuesday, May 15, 2007 - link

    Thank you for your response :)
  • cool - Tuesday, May 15, 2007 - link

    What am I missing? How can you have DDR2 800 results for the DDR3 Bearlake mobo?
    Look at the 3rd row, 4 column of the Sandra benchmarks results on page 5.
  • TA152H - Tuesday, May 15, 2007 - link

    Their chart is a little bit off. It is how they did their best to speed normalize DDR2 and DDR3, so for the DDR2 column for the Bearlake it is DDR2 memory they tested, for the DDR3 version, it is DDR3 memory.

    It's probably the most useful thing in there, in my opinion. It shows you get extra speed even at the exact same timings, with memory using lower voltage. It's pretty impressive.
  • cmdrdredd - Tuesday, May 15, 2007 - link

    not very impressive to me considering the prices you'll be paying. That's $300 difference between a good DDR2 kit and a DDR3 kit (probably not even high bin or binned at all).
  • TA152H - Tuesday, May 15, 2007 - link

    Well, agreed, currently you're not getting much bang for the buck, but that's always the case when new memory comes out. Look at the price of RDRAM, it never got better :P.

    But, obviously, the prices today mean essentially nothing for the future of the technology, it's just representative of it being a very new technology right now. I'd expect it should be a tiny bit more expensive everything else being equal because some of the additions to it, but it should be insignificant. It's a much cleaner design, and you get some performance on top of it, so I think it's a good technology. I agree, for now, it's difficult to validate the price of it. It's not even like you could say that you're better off getting a DDR3 based design now so you can reuse the RAM. The latencies are so poor on the current stuff you'd probably be aghast at using it a year from now, and you'd probably be able to buy 1 GB of DDR2 today, and 1 GB of DDR3 in a year for less than 1 GB today. So, right now, I don't think it makes much sense to anyone.

    Good thing for Intel pushing it though. Anyone that dislikes them needs to recognize how important they are for moving technology forward even at their own cost. Sometimes they've failed though, such as with RDRAM and, so far, EPIC.
  • Wesley Fink - Tuesday, May 15, 2007 - link

    DDR3 will run at DDR3-800 6-6-6-15 timings. We will add this to the DDR-800 5/6-6-6- line to clarify. The point was to run all 3 boards and the two memories at the exact same speed and timings. 800 was the only speed that allowed this.
  • cool - Tuesday, May 15, 2007 - link

    Thanks for the explanation, Wesley.
    I was confused thinking the P5K3 was maybe one of those motherboards that can take 2 types of different RAM, namely DDR2 and DDR3. But that is not the case.
  • TA152H - Tuesday, May 15, 2007 - link

    I see timings of 5/6-6-6-15 and such. What does 5/6 mean? The P965 is running at five and the others at six?
  • Wesley Fink - Tuesday, May 15, 2007 - link

    We added this clarification to Page 4 - Memory Test Configuration:

    "While memory timings were matched to the same memory speed wherever possible, there were a few settings where the chipsets did not allow a direct comparison. DDR3-800 runs at 6-6-6-15 timings. The P965 has options to set 6-6-6-15 timings but the board would not boot under any settings or voltage we fed it at 6-6-6 timings. The closest timings that would work on the P965 at 800 speed were 5-6-6-15. The P5K DDR2 board, based on the P35 chipset, would allow setiing and running 6-6-6-15 timings. This is reflected in our charts with the line ID of 5/6-6-6- for timings. We also tested DDR2 at the fastest timings it could achieve with complete stability on both the P5B Deluxe and P5K Deluxe. This was 3-3-3-9 at DDR2-800 and 4-4-3-11 at DDR2-1066."
  • TA152H - Tuesday, May 15, 2007 - link

    That's clear, I think that will remove any questions relating to the charts.

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