Kingston HyperX Red - 8GB (2x4GB) DDR3 1600MHz Memory Kit Review (KHX16C9B1RK2/8) - Test Setup & Overclocking
CPU: Intel i5-3570K
CPU Cooling: Cooler Master TPC 812
Motherboard: Gigabyte Z77X-UD3H
OS HDD: OCZ Agility 3 120GB SSD
Secondary HDD: Kingston HyperX 3K 240GB SSD
OS: Windows 7 Professional 64-Bit
We took several approaches to overclocking the Kingston HyperX Red kit. Since overclocking can be accomplished by lowering timings and/or clock speed, it can be a tricky business to find the perfect clock so there's no simple formula. Think of it as a race, where one racer is twice as fast as the other. The slower one gets to go first (lower latency, less wait time) but runs less fast. The faster runner (higher clock speed), has to wait a little bit longer to start running (higher latency) but catches up and passes with greater speed (higher clock). Now lets, for simplicity's sake, assume they arrive at the hypothetical finish line at the same time, both racers have the same relative speed. So with this analogy we can see that overall RAM speed isn't remarkably simple, and is a "tango" between clock speed and latency. Generally speaking, the faster runner will finish first, but often to increase that speed, he must take longer "rests," which somewhat offsets his gains. This is what we see by the diminishing return in memory overclocking by increasing the clock speed.
First, we wanted to see how low the timings could be set at the Optimized Default setting, which is 1333 MHz. We were able to get to CL7 with 7-7-7-22 timings, which is pretty good, but we weren't able to do any better than that. Next, we wanted to see how much lower the timings would go at the tested specification speed of 1600 MHz. I was a little surprised to see little flexibility for lowering the timings lower than the rated spec without failed POSTs and BSOD immediately upon boot, even as high as 1.65-1.70V. The rated timings (9-9-9-24) seemed to be about as low as they would go at 1600 MHz, which isn't that atypical, just luck of the draw (more like unlucky). Next, we tried for the best overall OC combination of timings and increase in clock speed. The kit seemed a bit more sensitive to to timing reduction, which I wasn't surprised about at this point. We were able to achieve the next step up at 1866 MHz and only had to drop the timings to 10-10-10-28, which is overall a pretty good setting. We weren't able to squeeze much more out of it, even at 1.7V, so we're content with the 1866 MHz setting we achieved. It's really not bad to achieve an 1866MHz clock on a kit that currently only costs $40 for 8GB.