Test System

Test Setup

As you can see, the Crucial memory is rather large in terms of height, so you want to make sure that these will fit next to your CPU cooler.

Performance & Overclocking

Usually we use CPU-Z to display the SPD programming, but since Crucial offers their own tool, let's use utilize that instead for this review. Crucial actually offers various profiles within the memory, from 457 MHz all the way up to 685 MHz. This is to insure maximal compatibility, while the single embedded XMP Profile allows you to run the kit at the rated speed of 1866 MHz with CL9 and 1.65V.

Starting at this setting the memory managed to perform perfectly right out of the gates, but interestingly enough - and as shown by many kits recently, there is not a lot of headroom with voltage scaling. In fact the kit performed worse the closer it got to 2V as we can see at CL6 for example. On the other end of the spectrum, even using 1.5V at the rated speed worked flawlessly and I managed to break 2000 MHz with this setting as well. Slightly relaxing the timings to CL10 also meant that the kit was able to run at up to 2322 MHz - very impressive. At this rating it is faster than the Ballistix 2133 MHz CL9-10-9 which is also available. A quick check confirmed that our 1866 MHz modules also managed 2133 with CL9-10-9 at 1.65V. Interestingly enough, a voltage increase did also increase the maximum overclock of the kit a bit.

The next step meant tightening the timings as much as possible. At CL5 the kit did not boot up properly, but at CL6-6-6 things look fine, as it managed 1333 MHz with 1.5V right away. Pushing the memory beyond 1.5V again, did not yield any improvement at all with such tight timings. Keeping CL6 the end of the line was 1434 MHz, while things took a turn for the worse at 2V - which is well beyond JEDEC standards or Intel specifications mind you - as the kit was only stable up to 1324 MHz. A similar problem occurred when raising the timings to CL7-7-7 as the memory managed to climb up to a maximum of 1652 MHz at low voltage, but dropped considerably when applying 2.0V. Things changed however when using CL8, as the memory did not only manage to run at the intended speed of 1866 MHz, but a raise in voltage actually yielded some smaller performance increases as well. Using 1.7V at most the kit managed 1900 MHz, at CL8. So it is nice to see that there is a good chance that your CL9 kit will manage to run at tighter CL8 timings right out of the box.




As you can see, setting higher voltage actually hampers the overclocking process, but also keep in mind that the results reflect what our kit was able to pull off and your mileage may vary!