Power Consumption

We measured the power consumption using Extech Power Analyzer 380803 device. This device was connected before the system PSU, i.e. it measured the power consumption of the entire system without the monitor, including the power losses that occur in the PSU itself. When we took the power readings in idle mode, the system was completely idle: there were even no requests sent to the hard drive at that time. We used LinX program to load the Core i7-860 CPU. For more illustrative picture we created a graph showing the power consumption growth depending on the increase in CPU utilization as the number of active computational threads in LinX changed.

System power consumption with Intel Core i7-860 processor working in its nominal mode is practically the same in case of static and dynamic Turbo Boost. The only thing I could point out here is slightly higher power consumption in idle mode with statics in place. During CPU overclocking, this difference becomes even more obvious.

Independent of the Turbo Boost implementation, the system power consumption in both cases is very similar. However, in idle mode the power consumption of an overclocked system with dynamic Turbo Boost is almost the same as with the CPU in the nominal mode, while with static Turbo Boost it is way higher. The thing is that when we enable C3-C7 states for dynamic implementation, we allow the CPU to switch to deep power-saving modes by disabling more units. That is why the difference between dynamic and static modes in idle mode is quite logical. However, I didn’t expect it to be so significant. Since more than 90% of the time the system is not really loaded heavily, those users who decide to go with static overclocking should keep in mind that in idle mode their system will be more energy-hungry.

The comparison between power consumption of LGA1156 and LGA1366 platforms is even more impressive. Besides two versions of Intel Core i7-860 CPU overclocking, we also added the results obtained during Intel Core i7-920 overclocking to 3.8 GHz using Gigabyte GA-EX58-UD3R mainboard.

During CPU overclocking, the difference lies between 30 and 60 W and although the graph only shows results during overclocking, the same is true for the nominal processor mode. Moreover, I have to say that Gigabyte GA-EX58-UD3R is a very energy-efficient mainboard for LGA1366 standards. It has very effective processor voltage regulator circuitry, doesn’t have additional PCI Express bus controller. Besides, we overclocked Intel Core i7-920 without increasing its Vcore, unlike Intel Core i7-860. All in all, LGA1156 and LGA1366 platforms are totally incomparable in terms of power consumption.