Theoretically, the typical heat dissipation of all Cougar Point chipsets, including the new Z68, is the same and equals 6.1 W. However, practical power consumption measurements taken for P67 and Z68 based mainboards revealed pretty interesting peculiarities.
The graphs below show the full power draw of the computer (without the monitor) measured after the power supply. It is the total of the power consumption of all the system components. The PSU's efficiency is not taken into account. The CPUs are loaded by running the 64-bit LinX 0.6.4 utility. We enabled C1E and Enhanced Intel SpeedStep power-saving technologies for correct measurement of the computer's power draw in idle mode.
Even in idle mode Asus P8Z68-V PRO and Asus P8P67 PRO mainboards with identical functionality and performance consume different amounts of power. The Intel Z68 based solution is a few watts more resource-hungry than its predecessor.
The newcomer consumes noticeably more power under single-threaded load as well as during full CPU utilization.
So what’s the matter? It is important to remember what we said when we studied the voltage regulator circuitry layout on the new Asus P8Z68-V PRO mainboard. It has four additional phases powering Intel HD Graphics 2000/3000 core. P67 based mainboards do not have these phases at all.
It means that mainboards based on the new Intel Z68 chipset supporting integrated graphics power the graphics core anyway, even if the add-on graphics card is used. In fact, this is exactly what Lucid Virtu technology is based upon (we are going to talk more about it later in this review). As for Intel P67 based mainboards, they do not imply that the graphics core integrated into the processor may be involved at all, so they do not send any power to it. As a result, P67 based systems turn out a few watts more energy-efficient in any case.