Test Setup

Performance & Overclocking

Before We Get Started

The new Core i7 in combination with the X58 is quite different than previous generations of Intel CPU & chipset combinations. The fact that the tri-channel memory controller is located inside the CPU poses a few unique limitations for memory makers. While we always bench DDR3 between 1.5 V and 2.0 V, this spectrum is not possible with the Core i7. Intel advertises and only guarantees up to 1.65 V on the memory, because the memory controller has now been placed on the CPU die. This means that there is a lot less room for higher clocks and it will be interesting to see how the memory fares at this maximum allowed voltage. There is no point in pushing everything further, risking to fry our plattform or enticing you to risk yours, by presenting you with results usually not safely attainable.

It should be noted that overclocking on the Foxconn Bloodrage is an art of its own. While most boards will only give you options which tend to be within certain specifications, the Bloodrage gives you all the choices within the BIOS. This means that you may set something which will make your system not boot, even if the components can take the overclock. One thing you should always watch for when OCing an i7 is the fact that the frequency of the onboard memory controller should be set to twice the speed of the memory you are running.
This is simply achieved by setting the multiplier twice as high for the controller compared to the memory. The CPU voltage has been bumped to 1.45 V and any automatic fan control turned off, so that the Noctua CPU cooler blows full force all the time. Preliminary testing of our specific Bloodrage and i7 CPU seem to point to a possible base clock of 200 with a CPU speed of 4 GHz. Just to make sure, various other voltages have been tweaked to the maximum to allow the best possible overclock on the i7 920 - in fact we are even pushing the northbridge voltage and the so called "UnCore" voltage into the red numbers, to make sure that the CPU & mainboard are not the ones holding us back.

Base Settings

This section is new and illustrates what settings were used to attain the advertised speed of the memory sample in this review:

• Base Clock: 160 MHz
• CPU Multiplier: 20x
• CPU Speed: 3200 MHz
• CPU Voltage: 1.45 V
• CPU VTT (UnCore) Voltage: +220 mV
• X58 I0H Core Voltage: 1.24 V
• Memory Multiplier: 10x

These are just what our Foxconn Bloodrage board booted easily with to reach the Base Clock and resulting 1600 MHz memory speed.

Performance

First off, we openend up CPU-Z to check the programming of the modules. It looks like Mushkin has a correct XMP profile embedded in the DIMMs. This should make it easier to run them at the advertised speed right out of the box.

Starting out with the settings above, we did a complete run to give you the numbers you can expect when using this memory. First off, trying to boot the memory at CL5 did not seem to work, but setting it to CL6 did the trick. So we worked our way through each CL between 6 and 9, with a quick check at CL 10 to see if the memory would manage more. Only the onboard memory controller requires a 2:1 ratio to the memory. From this point we simply pushed the base clock and managed to raise it all the way up to 203 MHz. This means that the memory was running at 2030 MHz. This was the highest attainable memory speed. This means that the CPU was running at 4.06 GHz, which is a great OC for an Core i7 920 on air. Past this speed the system became unstable no matter how relaxed we set the memory timings. This could be because we are reaching the limit of the memory or the CPU.

Now that we know what the memory is capable of, let us take a look at what it managed out of the box. Mushkin rates the Redlines at 6-7-6-18 with 1600 MHz, which worked flawlessly right after setting that. Trying to push them higher without adjusting the CL rating in any way on the other hand was not possible at all. The system became unstable after speeding the system up just a few MHz on the base clock. Setting the memory to 6-6-6 on the meant that we could not boot them at 1600 MHz, managing only 1490 MHz. So Mushkin seems to set this kit as tight as possible at 1600 MHz. Relaxing the timings to 7-7-7 raised the overclockablity considerably to a good 1734 MHz, but we were always able to push the memory higher with looser timings. At CL8 we broke the 1900 MHz wall and at CL9 we finally cracked the 2000 MHz. Changing the voltage at each CL rating from 1.5V to 1.65V seemed to give us a bit better overclockablilty. Most of the time, the difference is quite small, with the exception of CL7, where we managed to tickle around 100 MHz more out of the kit at maximum voltage.




As you can see, pushing the voltage yields improvements in performance between a mere 20 MHz or even a full 100 MHz. Seems like the sweet spot for our sample was with CL7, where we saw the largest jump. Remember - your milage may vary!