Testing Method & Test Setup
To test the overclocking capabilities of the memory we are going to use Intel’s
recently released Haswell platform. As memory overclocks are known to vary between
different motherboards, we are going to perform the tests using two different
platforms to be sure that our numbers are reliable.
Motherboard |
ASUS Maximus VI Gene (BIOS 0607)
Gigabyte Z87X-OC (BIOS F5s) |
CPU |
Intel Core i7-4770K ES @ 4.0 GHz |
Graphic
card |
ASUS GTX 580 |
Memory |
Corsair Vengeance Pro CMY16GX3M2A1866C9 |
SSD |
Samsung PM840 Pro |
PSU |
Seasonic Platinum 660 Watts |
OS |
Windows 7, 64 bit SP1 |
Even though Haswell is very flexible on the memory frequency one can set, very few
people actually do base clock (BCLK) overclocking on their daily setups.
Therefore, instead of our previous procedure of fixing the voltage and raising
the frequency in 10MHz steps we are now going to fix the frequency and minimize
the voltage in 0.01V steps.
As usual, our stability method of choice is HCI Memtest.
Since we are dealing with an 16 GB kit, we use eight 1500 MB instances and call
things stable if we see all of them to go past 100% without showing a single
error.
Not to get things too complicated, we only set the primary timings, command rate
(1T) and the memory voltage by hand while the rest of the settings is left for
the motherboard and SPD to agree on.
Results
As we were dealing with memory based on chips we might not have had before, we had to start from scratch, i.e. try every possible timing combination. After some time, we managed to narrow things down to eight timing combinations that made most sense. Also, we discovered that maximum stable frequency is a function of voltage, but whereas Micron chips of the older days could scale up to 2.0V with ease, these new ones were already having stability issues running at 1.8V.
In the end, we were able to get the memory running at DDR3-2000 with 8-9-10-24 and DDR3-2200 with 9-9-10-27, both times without exceeding a psychological voltage barrier of 1.65V. We could also achieve stability at 1200MHz, a.k.a. DDR3-2400 but doing so required loosening up the timings and pushing the voltage past 1.7V so it might not be the best thing to do from a daily user’s perspective.