System Builder Marathon, Q4 2012: $2,000 Performance PC

Overclocking

We chose Gigabyte's Z77X-D3H based on our own recommendations. And yet, we suggested the Gigabyte board for enthusiasts on a more limited budget. We had apparently forgotten why the company's -D3H-series motherboards had previously been left out of our high-end builds since last year, only to remind ourselves on overclocking day.

We wanted a constant voltage level between 1.25 and 1.30 V. But the Z77X-D3H's voltage regulator simply couldn’t do what we asked under the rigors of overclocking. Setting the firmware’s Loadline Calibration setting to High kept the voltage where we wanted for a while. But, again, full-load testing stress caused a protection circuit to reset the system. The same safeguard keeping us from destroying the board instead inhibited our overclock, even though the processor was never active for long enough during real-world testing to exceed 70° Celcius.

The Medium Loadline Calibration setting allowed the core to drop to around 1.23 V under full load, in turn limiting our processor's maximum clock to 4.4 GHz.

The issues didn’t end there however, as the Core i7-3770K eventually climbed to 84° Celcius, even at our more conservative settings. Had we picked a motherboard better able to contend with aggressive overclocking, the mediocre heat sink and fan would have been our next bottleneck to address.

A combination of overclocking consistency and value pricing put G.Skill's 8 GB DDR3-1600 kit in our system. Proof of that consistency came when it achieved the same DDR3-2133 data rate at 10-11-10-24 timing seen in our previous $2,000 build.

Graphics cards tend not to be as flexible as host processors when it comes to voltage levels and overclocked frequencies, but we didn't need any more voltage to push the limits of MSI’s Radeon HD 7970 cards.

Automatic fan speed wasn’t sufficient for our overclocked settings, though. So, we set a simple slope in MSI Afterburner’s advanced settings. We also set “Start With Windows” and “Start Minimized” under the program’s General tab.

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  • Steveymoo
    I was getting ready to whine about power consumption with those AMD cards, but it looks like they're not so bad! I'd be interested to know how loud/whiny this system gets, and how it would perform with 2 gtx 680s instead.

    Also, I find it weird that those crossfire GPUs fall flat on their face at 2560 resolution in some games. Is there some kind of crossfire/gpu memory issue going on there?