DDR3 vs. DDR2

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.