DDR3 vs. DDR2

by Wesley Fink on May 15, 2007 2:40 PM EST
Number Crunching and Gaming

We now know that that the only real improvement in our tests is a 16% to 18% improvement in memory bandwidth on P35, whether it is running DDR2 or DDR3. The next question is whether that bandwidth improvement translates into any real improvement in system performance.

To look at pure number crunching, SuperPi 1.5 was run in all memory test configurations. SuperPi is a very simple program as it merely calculates the value of Pi to a designated number of decimal positions. In this case we chose 2 Million places.

Super Pi 1.5 - 2.66GHz
Time in Seconds - Lower is Better
Memory Speed P965
ASUS P5B Dlx
P35 DDR2
ASUS P5K Dlx
P35 DDR3
ASUS P5K3 Dlx
DDR2-800 3-3-3-9 46.05 45.06 -
DDR2-800 5/6-6-6-15
DDR3-800 6-6-6-15
47.28 46.08 45.96
DDR2-1067 4-4-3-11 45.39 44.47 -
DDR2-1067 5/6-6-6-15 45.72 45.02 -
DDR3-1067 7-7-7-20 - - 45.11
DDR3-1333 9-9-9-25 - - 44.96

It is interesting to see that the improvement in memory bandwidth on the P35 does translate into faster scores on SuperPi 1.5. As stated many times memory is just one part of a complete system, so a 16% to 18% improvement in memory bandwidth will translate into much smaller increases in system performance.

With pure number crunching, the P35 yields a 2% to 3% improvement in SuperPi results. While this is a small improvement, it is consistent across speeds and test results. As seen in the memory bandwidth results, the performance difference is the P35 chipset, and not the DDR3. It really doesn't matter if you run DDR2 or DDR3 on the P35; you will get slightly better number crunching performance with P35.

Gaming

A standardized game benchmark was chosen from our memory test suite to determine if the better P35 memory bandwidth improved gaming performance. The Far Cry - River demo was run for 3 loops and results in FPS were averaged over the 3 runs.

Far Cry - HOC River
Frames Per Second - Higher is Better
Memory Speed P965
ASUS P5B Dlx
P35 DDR2
ASUS P5K Dlx
P35 DDR3
ASUS P5K3 Dlx
DDR2-800 3-3-3-9 101.26 102.91 -
DDR2-800 5/6-6-6-15
DDR3-800 6-6-6-15
97.76 99.93 100.27
DDR2-1067 4-4-3-11 103.04 108.02 -
DDR2-1067 5/6-6-6-15 102 106.61 -
DDR3-1067 7-7-7-20 - - 102.29
DDR3-1333 9-9-9-25 - - 103.18

We were really surprised at the gaming test results. We really did not expect the bandwidth improvement of P35 to have much impact on gaming results, but Far Cry showed a 2% to 5% improvement in performance just comparing P35 to P965 under the same conditions. It really didn't matter whether P35 was running DDR2 or DDR3; the improvement was essentially the same.

Having said that it should be clear from these results that gaming responds well to lower (faster) memory timings, which is why the 800 3-3-3 and 1067 4-4-3 results top the results charts. However, the promise of DDR3 is evident in the fact that 1067 at the slow 7-7-7-20 timings performs nearly the same as the P965 at 4-4-3, and at the very slow 1333 9-9-9-25 DDR3 outperforms DDR2 4-4-3 on the P965. Results for DDR2 on P35 at these same fast timings are, however, the fastest test results in the comparison.

At the same speed and timings DDR2 and DDR3 perform virtually the same in gaming on the P35, and they are faster than DDR2 on the P965. DDR3 at the same timings may have a very slight performance advantage over DDR2 on the same platform, but it is too early to reach that conclusion. The results for DDR3 at 1067 and 1333 timings do make us look forward to DDR3 at faster memory timings. It is good now, and with better timings DDR3 will likely be great at these higher speeds.

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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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