X-bit labs

Intel Core 2 Extreme QX6700 and Core 2 Quad Q6600 Processors: Quad-Core CPUs Gone Real! (page 11)

Category: CPU

by Ilya Gavrichenkov

[ 11/01/2006 | 10:31 PM ]

Power Consumption

Core micro-architecture has already proven extremely economical and efficient from the performance-per-watt prospective. Conroe processors that we have already tested before turned out not only the today’s fastest desktop CPUs but also consumed the least power of all. For example, Intel declared the typical heat dissipation for their Core 2 Duo E6700 at only 65W. The new quad-core processors are built with two Conroe cores inside, so their typical heat dissipation doubled. So, the quad-core Core 2 Extreme QX6700 working at the clock speed of Core 2 Duo E6700 dissipates 130W of heat. Therefore, theoretically it boasts the same heat dissipation as Pentium D processors on Presler core. I have to admit that it might be a very alarming sign for those of you who very well remember what kind of cooling systems were required for the last NetBurst processors. However, before we make any final conclusions, let’s take a look at the practical benchmark results, maybe things are not as threatening as they might seem at first glance. So, we will measure the processors power consumption that equals their heat dissipation according to the energy conservation law.

As always, we used a special S&M utility to measure the maximum power consumption (you can download this utility here). We measured the current that goes through the CPU power circuitry. So, the numbers given below do not take into account the efficiency of the CPU voltage regulator laid out on the mainboard.

First of all, we measured the processors power consumption in idle mode. Cool’n’Quiet, Intel Enhanced SpeedStep and Enhanced Halt State power saving technologies were disabled in this test.

Well, we do not observe anything alarming in idle mode. Core 2 Quad Q6600 consumes almost as much as the dual-core Core 2 Extreme X6800 on Conroe core. As for the power consumption of the quad-core Core 2 Extreme QX6700, it is 8W higher, but still lower than the power consumption of Athlon 64 FX-64 processor in the same testing conditions.

Now let’s see what the results will be in case of 100% CPU utilization.

As we can see, the practical power consumption of Kentsfield processor is 75% higher than that of Conroe CPU working at the same clock frequency, which is pretty close to the theoretical numbers. However, despite this fact the new quad-core Intel processors are still more economical than the dual-core Athlon 64 FX-62 and the latest revisions of the dual-core Presler based CPUs.

In other words, you shouldn’t really worry about the high heat dissipation of the new Kentsfield processors. Our test session suggests that from the heat dissipation prospective Core 2 Extreme QX6700 is comparable with AMD Athlon 64 X2 5000+, and Core 2 Quad Q6600 – with the Energy Efficient modification of Athlon 64 X2 4200+.