OCZ 6GB PC3-12800 Platinum DDR3 Triple Channel Memory Kit Review | ||||||||
| by MAC | March 15, 2009 | ||||||||
| Overclocking Results Overclocking Results For our overclocking tests we are interested in two main elements, how well the memory scales with additional voltage and how versatile it is at overclocking with different timings. As mentioned in the methodology, our overclocking efforts will primarily focus on four basic timings configurations (7-7-7 / 8-8-8 / 9-9-9 / 10-10-10) and three different voltage settings (1.55V / 1.65V / 1.75V). The CPU frequency will be kept as close as possible to the stock 3.2Ghz, while the Uncore and QPI Link will be kept near 3200Mhz and 6400Mhz respectively, multipliers permitting. The QPI/DRAM voltage was kept at a relatively high 1.4785V (BIOS)/1.45V (measured via digital multimeter) throughout our tests, in order to ensure (as best as possible) that the integrated memory controller would not bottleneck our memory overclocks. The IMC is without a doubt the determining factor in achieving high memory clocks, and every single Core i7 processor will have different headroom when it comes to memory clocks it can achieve. With the pleasantries out of the way, let's get to the fun stuff.  Now obviously everyone is going to have the same question on their mind, so let us get it out of the way. The apparent limit at 1922Mhz is, much to our dismay, the highest memory frequency that our engineering sample Core i7-965 XE can handle stably with 1.45V QPI/DRAM voltage. From what we are seeing on enthusiasts forums throughout the interweb, most of the retail chips have a much better integrated memory controller (IMC) than our sample, and can hit higher clocks and often with much lower voltage as well. So with that out of the way, let's get to the memory kit itself. As you can see by this chart, this particular memory kit really took off once we started loosening the primary timings. Whatever they are, the ICs that OCZ have selected for this model are obviously quite flexible and overclocking-friendly. They also scaled very nicely with additional voltage, which is something that we did not see in our review of the G.Skill F3-12800CL9T-6GBNQ. Achieving over DDR3-1800 9-9-9 at a mere 1.55V is a very good result, as is almost reaching 1900Mhz at the same very low voltage. At 1.65V, the kit continued to scale nicely until it was bottlenecked by our Core i7's IMC limit at the 1922Mhz mark. Surprisingly our sample needed the full 1.65V to achieve its rated DDR3-1600 7-7-7 speeds and there was no headroom above that. This is within specification for this model, but either our sample was a little poor in the CAS 7 overclocking department or OCZ is binning these modules very aggressively. We believe that the former is true, and we likely just got unlucky this time around. By upping the memory voltage to 1.75V, we once again hit our IMC limit, but this time with improved 9-9-9 timings. We have seen samples of this model achieve well over 2.0Ghz (with healthy doses of voltage), and we have no doubts that we would have achieved this milestone too with a better processor. It should be noted that once you started pumping more than 1.75V into these modules they do get quite toasty and they definitely benefit from active cooling to maximize stability and overclocking potential. We definitely continue to be impressed by this new generation of DDR3 memory kits, which have been specifically designed for low voltage operation as per the needs and requirements of the Core i7 processors. Just six months ago it would have totally laughable to suggest that you could buy a 6GB DDR3-1600 7-7-7 kit for $150CDN, and it would be as absurd to suggest that it would be able to overclock to over 1900Mhz with only 1.55-1.65V. This memory kit may not be able to surpass Corsair's best, but it can certainly give their mainstream kits a good run for their money...and for less of it! Since we like to provide our readers with ample evidence of our overclocking achievements, feel free to peruse the four screenshots below:
Now that we have tested this memory kit's overclocking prowess, and revealed that it can handle a wide range of speeds and timings, let's see how it handles the benchmarks. Do the low 7-7-7 timings make a difference over the more standard 8-8-8 and 9-9-9? That is what we will be examining next in our benchmarking section.         | ||||||||
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