The default settings for the Core i7 4770k are shown above – the multiplier is set at 35 (x100), giving the final speed of 3,500mhz. The turbo function allows for boosts to 3,900mhz, the same as the ASUS Z78 Sabretooth which we also reviewed for launch today.
We configured the Corsair H100i cooler fans and pump to ‘performance’. There is very little if any difference using ‘maximum fan settings’ as the cooler was reaching its limits under load.
Overclocking the Gigabyte GA-Z87X-OC proved straightforward enough. Inside the Frequency submenu of the Performance tab are various settings to adjust the PCIe Clock frequency, processor graphics clock and the processor frequency itself.
With the Core i7 4770k installed, we could access a range of automated range settings for the Core i7 4770k – we selected the ‘4.5GHZ’ option. It didn’t change any of the voltage settings however, so we still had to manually adjust those.
We changed the CPU Vcore voltage to 1.225V.
The 3D Power Control panel contains the Loadline Calibration and the PWM Phase Control settings. These can be useful to enhance stability at overclocked speeds. We used a mixture of ‘extreme’ and ‘high perf’ with the voltage of 1.225 to achieve stability at 4.5ghz.
Our 4770k sample seemed to be hot running (we checked with a diode connected directly to the core) and we tested with several motherboards and coolers before launch. At 1.25V or above the temperature could easily hit 90c+ under load. At 1.225V with a Corsair H100i the 4770k temperatures would hover around 82c, which is certainly safer long term.
System validation at 4.5ghz is available over here.
Not enough? … Well lets see how high we could get a (unstable) post into Windows.
With 1.35 volts and the loadline calibration and PWM Phase Control settings close to maximum we got a post at 4.9ghz – the temperatures of the processor hit more than 100c however. We do need the 4770k for other reviews and content, so immediately backed down. This was obviously not close to Prime stable either.
Remember, it is always important to use an overclock and voltage settings that won’t kill the processor over time … unless you are rich or make a living out of overclocking hardware to the limits.