Let us continue with the most important part of the test report, the highest possible stable performance. The multiplier adjustment remains on 13x 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 7 RC Ultimate Edition is used as the operating system. The stability was examined with the software Memtest86
and SiSoft Sandra Lite 2009 SP3 program is used for all benchmarks, since it offers extensive adjustments and a fast result comparison. BTW. the latest SiSoft Sandra 2009 version is available on our download server and can be downloaded much faster. All benchmarks are also included in the free Sandra Lite version.
First the maximum possible frequency of the memory module was determined with default 1.50 Volt (1,53V). The memory frequency was increased in small steps with a fixed memory timing of 8-8-8-24 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 8-8-8-24 2T (CAS-TRCD-TRP-TRAS) timings and 1.53V was 750 / 1499 MHz. If you’ve read both previous highend DDR3 module reviews, you already know such a frequency result, because on this low voltage the frequency was identical to the much faster modules.
Here is a Snipping screenshot of CPU-Z with 750 / 1499 MHz and 8-8-8-24 2T with 1,53 Volt:
Of course it’s possible to run much higher frequencies with increased voltages or lower timings, because the frequency values and timings depends directly from each other. But officially Crucial specify only a voltage of 1.50 Volt without loosing the warranty. The voltage should not be increased very much without further cooling modifications.
The benchmark comparison of all DDR3 memory modules were tested with the default 1.53 V, where these Crucial 4GB modules reached 1499 MHz. This highest possible clocking on the default DDR3 voltage was compared now with two other settings. On the one hand they were tested with 200 MHz reference clock x6,66 = 1333 MHz and SPD values (SPD values are programmed in the SPD IC by the manufacturer). On the other hand the highest possible frequency with the permitted manufacturers voltage was determined at 8-8-8-24 2T. But in case of these modules the highest voltage is identical with the lowest test voltage, so the second test is equal to the first result.
With a frequency of approx. 667 MHz the timings by SPD EEPROM autodetection were 9-12-12-30 2T (CAS-TRCD-TRP-TRAS).
Here is a Snipping screenshot of CPU-Z with 666.7 / 1333 MHz and 9-12-12-30 2T:
Here are the SiSoftware Sandra 2009 benchmark results:
| Frequency | Timing | Memory Voltage | RAM Range Int Buff’d iSSE2 | Memory Bus Range | Memory Latency |
| 225 MHz * 6,66 = 1499 MHz | fix (8-8-8-24 2T) | 1.53 Volt | 13,48 GB/s | 23,44 GB/s | 75 ns |
| 232 MHz * 6,66 = 1499 MHz | fix (8-8-8-24 2T) | 1.53 Volt | 13,48 GB/s | 23,44 GB/s | 75 ns |
| 200 MHz * 6,66 = 1333 MHz | SPD (9-12-12-30 2T) | 1.53 Volt | 11,84 GB/s | 20,84 GB/s | 93 ns |
By the way, the “Memory Bus Range” is no benchmark value, but this value is quite simple to calculate by the frequency and this is useful for a benchmark comparison.
Here’s a diagram of the benchmark values:
Here is a direct benchmark result comparison of some DDR3, DDR2 and DDR memory modules:
The Crucial PC3-10600 CL9 kit achieved identical overclocking results with JEDEC standard voltage of 1.50 V as for example the previous tested OCZ PC3-12800 CL8 kit on 1,50V or the Lexar Media Crucial Ballistix tracer PC3-10600 CL6 kit. At the first look this is very amazing and also very welcome on such a low price. However, the other two DDR3 kits are provided with heat spreaders and can be operated with much higher voltages. The last one makes it possible to increase the frequency much higher and thus also increase the performance.