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 F5q)
CPU	Intel Core i7-4770K ES @ 4.0 GHz
Graphic card	ASUS GTX 580
Memory	GSkill Trident-X F3-2666C11D-8GTXD
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 a 8 GB kit, we use eight 750 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

Traditionally, our aim is to see how memory reacts to voltage changes and in case with Hynix CFR this reaction translates in almost linear ability to run higher frequencies without having to raise the CAS latency. What comes to second and third entries in the primary timings list, tRCD and tRP, the main factor for lowest stable values of 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.
We did not test our memory much above 1.80V as we are not sure whether such voltages are suitable for daily use. Keeping things below 1.80, we were able to achieve stability at DDR3-2400 with 9-11-10-27, DDR3-2666 with 10-13-12-32 and DDR3-2933 with 11-14-13-35 none of which is a bad result. As can be seen, raising the CAS latency above 11 does not provide much of an improvement; the only thing CL12 theoretically gained is fitting this pair of modules inside a 2800C12 specification.
Looking at state of things in general, Hynix CFR seems to be a very decent option not only for Ivy Bridge, but also for Haswell-based setups since its “best at” range of DDR3-2400 to DDR3-2800 perfectly matches the “best at” range of memory controllers when it comes to daily stable memory clocks.

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Page 1 - Introduction

Page 2 - Closer Look

Page 3 - Photo Gallery

Page 4 - Results

Page 5 - Conclusion