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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  • Final Hamlet - Tuesday, May 15, 2007 - link

    Oh look! It's Bicycle repair man!
  • just4U - Wednesday, May 16, 2007 - link

    I don't really know what to think with ddr3 .. or even ddr2.

    When I jumped from PC 2700 memory (cas 3 i think) up to PC3200 memory cas 2 I noticed a increase in the overall speed of my computer.

    When I jumped to DDR2 PC5300 I noticed no speed increase. When I jumped to PC6400 I noticed no speed increase. When I overclock my memory I notice no...

    You get the picture.

    I have a question. DDR3 with tight timings, Will we accualy notice it over ddr2? Or will it be one of those things where only a benchmark tends to notice anything.
  • Starglider - Friday, May 18, 2007 - link

    Depends on what applications you're running. But based on your recent experience, probably not.
  • defter - Tuesday, May 15, 2007 - link

    The article says that P965 board was running at 1066MHz FSB and then writer is suprised when P35 + DDR2 running at 1333MHz FSB is slightly faster??? Then in the conclusion it's said that the reason for an increased performance is the chipset instead of a higher FSB???

    If you want to make P965 vs P35+DDR2 comparision, why not use the same FSB.....
  • Wesley Fink - Tuesday, May 15, 2007 - link

    The P965 was running at 10x266 or 2.66GHz. The P35 boards ran at 8x333 or 2.66GHz. 1333 is not a natural CPU ratio on the P965 so when you choose 1333 there is no way to also choose DDR2-800. At 1333 the closest you can get (at a different strap) is 833. We believe the way we tested was as close to apples to apples as we could design. Remember we are looking at MEMORY PERFOMNACE, and the FSB should not matter as long as memory speed and timings are set the same on all test boards, which we definitley insured.

    Despite that, we know that Sandra XI results can be influenced a small amount by CPU speed and possibly FSB. To make sure our results were still as close to apples to apples as possible we did run 10x266 on all boards and compared results to our test setup. The MEMORY PERFORMANCE results were virtually the same as we have reported.

    We do agree that were we testing CPU performance the differing bus speeds at the same resulatant CPU speed could make some difference.
  • IntelUser2000 - Wednesday, May 16, 2007 - link

    quote:

    Despite that, we know that Sandra XI results can be influenced a small amount by CPU speed and possibly FSB. To make sure our results were still as close to apples to apples as possible we did run 10x266 on all boards and compared results to our test setup. The MEMORY PERFORMANCE results were virtually the same as we have reported.


    Defter is right. You guys were just testing performance increase by using a 1333FSB instead of 1066FSB. Memory bandwidth tests like Sandra will show HUGE differences. Remember, the CPU will not benefit from faster memory when FSB isn't faster. It's different from AMD where Hypertransport is only used for northbridge to southbridge communications(which yields into 0% improvement ) for PC.
  • Wesley Fink - Wednesday, May 16, 2007 - link

    P35 is a combination of an increase in bus speed to 1333 and an improved memory controller. We are working on a followup article to appear in a few days that shows the breakdown of the bus speed contribution and the memory controller contribution.

    That does not change the fact that memory bandwidth for P35 is improved 16% to 18% over P965, but we have run additional tests to show the individual impact of the bus speed increase and the memory controller improvements.

    In approaching testing it is not possible to run 1333 FSB on the P965/975x and also run memory speeds like 800 and 1066 as we would like. On P35 if 1066 FSB is selected then 1333 is not available as a memory option. We can, however, run 1066 FSB on P35 to roughly determine Memory Controller contribution compared to P965, and then compare those results to 1333 equivalents (8X333 instead of 10x266) to see the additional impact of the 1333 bus on memory performance. Those results will be reported as soon as testing is complete.
  • defter - Wednesday, May 16, 2007 - link

    quote:

    1333 is not a natural CPU ratio on the P965 so when you choose 1333 there is no way to also choose DDR2-800


    Why not report results at 1066MHz FSB then?


    quote:

    Remember we are looking at MEMORY PERFOMNACE, and the FSB should not matter as long as memory speed and timings are set the same on all test boards, which we definitley insured.


    Intel's CPUs are FSB limited since memory traffic goes through FSB. For example, 1066MHz FSB can transfer 8.5GB/s while dual channel DDR2-800 can provide 12.8GB/s. Thus, increasing the FSB also affects memory performance.
  • vaystrem - Tuesday, May 15, 2007 - link

    I'm curious:
    A) Why did you chose Farcry?
    B) Why you didn't include more game tests?

    I think it would be particularly interesting to see how a game like Supreme Commander or Company of Heroes performs. In strategy games you have the stress from the graphical component and a heavy AI load which may take better advantage of all that bandwidth than a simple FPS.
  • Wesley Fink - Tuesday, May 15, 2007 - link

    This was a comparison of DDR3 and DDR2, not a launch review for P35. You will see that when the performance embargo lifts on May 21st. Far Cry is part of our standard memory test suite and we are very familiar with how it behaves with variations in memory bandwith and timings. That is why it was chosen.

    You will see test results with many more games when we review the chipset on May 21st and the new P35 motherboards on June 4th.

    Consider this a preview, and all the advance info we could give you at this point. The NDA for DDR3 memory has lifted, but the performance NDA for P35 is in place until the 21st.

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