CPU on different frequencies depending on the reference clock for the different memory benchmarks. Thus the multiplier adjustment remains on 9x with all frequencies, because an adjustment for the CPU in half multiplier steps would be too inaccurate to get nearly the same CPU frequency for all tests.
Microsoft Windows XP Professional SP2 is used as the operating system. The stability was examined with the software Memtest86
and SiSoft Sandra Lite 2007.SP1 program is used for all benchmarks, since it offers extensive adjustments and a fast result comparison. BTW. the latest SiSoft Sandra 2008 version is available on our download server and can be downloaded much faster and very easily – ALL benchmarks are also included in the free Lite version.
First the maximum possible frequency of the memory module was determined. The memory frequency was increased in small steps with a fixed memory timing of 4-4-4-10 2T and default memory voltage, as long as the detailed memory test with Memtest86 runs without any errors. This quite long testing time ensured that this frequency works really stable with these modules.
The highest possible frequency with 4-4-4-10 (Tcl Trcd Tras Trp) timings was stable with 347 MHz !
Of course it’s possible to run higher frequencies with increased voltages or lower timings, because the frequency values and timings depends directly from each other. Officially Crucial specify the highest voltage of 1.8 V without loosing the warranty. But overclocking is usually higher than the specification, so with heatsinks it should be possible to give them more voltage.
This highest possible frequency was compared to two other settings. On the one hand 347 MHz with SPD values (these are given by the manufacturer in the SPD IC), and on the other hand 200 MHz (x2) with SPD values.
By the way, the “Memory Bus Range” is no benchmark value, but this value is quite simple to calculate by the frequency and is useful for the benchmark comparison.
Here’re the benchmark results:
| Frequency | Timing | RAM Range Int Buff’d iSSE2 | Memory bus range |
| 347 MHz | fix (4-4-4-10 2T) | 5596 MB/s | 11072 MB/s |
| 347 MHz | SPD (4-4-4-12 2T) | 5596 MB/s | 11072 MB/s |
| 200 MHz | SPD (3-3-3-9 2T) | 4619 MB/s | 6432 MB/s |
Here’s a diagram of the benchmark values:
Here is a direct benchmark result comparison of some DDR2 and DDR memory modules:
The results of the Crucial PC2-4200 CL4 of memory modules are slightly over the PC2-4200 ECC modules, whereby these memory modules were equipped with the additional chip for the error correction. ECC has a slower benchmark result in spite of higher overclocking frequency and higher memory bus range. The 1GB PC2-4200 modules with Micron D9HNH can be set to DDR2-667 in the BIOS, but without much more OC.