Testing Method & Test Setup
To test the overclocking capabilities of the our kit, we are going to use an overclocked Intel Haswell platform due to its fast memory controller, which allows for all testing to be done within a reasonable period of time.
Motherboard |
ASUS Maximus VI Impact (BIOS 0217) |
CPU |
Intel Core i7-4770K @ 4.5 GHz |
Graphic card |
ASUS GTX 580 |
Memory |
Corsair Vengeance Pro CMY8GX3M2B2933C12R |
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, we fix the BCLK frequency at default 100MHz, only adjust the memory multipliers and then minimise the voltage for each given setting.
As usual, our stability method of choice is HCI Memtest. Since we are dealing with an 8 GB kit, we use eight 750 MB instances and call things stable if we see all of them to go past 150% 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 are left for the motherboard and SPD to agree on.
Results
Traditionally, our aim is to see how memory reacts to voltage and timing adjustments and in case with Hynix MFR we have an almost linear dependance between stable frequency and voltage using a constant CAS latency. What comes to second and third entries in the primary timings list, tRCD and tRP, the main factor for lowest stable values for those is frequency, with voltage playing a role only in borderline areas. Lastly, the tRAS value we use in each part of the testing is a sensible value induced by an educated guess.
A good indicator of quality on Hynix is voltage required for stability at DDR3-2800 at CL11. The yard stick in this case would be 1.70V with truly great sets being able to go under 1.65. In case with our Vengeance pro, we have a value of 1.72V, which isn’t exactly what we would call good.
Another bad sign is the voltage headroom that Corsair have left for specs at 1466MHz CL12. Given that some motherboards can undervolt the memory by more than 0.01V compared to what is set in the BIOS, we see a potential source of stability issues for those who only use XMP.
On a positive note, the memory is very flexible in terms of the timings it can run at lower frequencies and, given a good enough memory controller and enough voltage, can also be stable above
DDR3-3000.