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Power Consumption

Although we managed to find a set of applications where Bulldozer performance is fairly good, the CPUs based on this new microarchitecture are far from being considered revolutionary. Our only hope at this point is the power consumption, because previous AMD processors were way behind their competitors in this aspect. Now, however, the new microarchitecture is promised to be much more energy-efficient. Plus the new finer 32 nm process should have contributed to the improvement of the electrical characteristics of the new processors. so, let’s check out the performance-per-watt of the new FX-8150.

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 all the power-saving technologies for a correct measurement of the computer's power draw in idle mode: C1E, C6, AMD Cool'n'Quiet and Enhanced Intel SpeedStep.

In idle mode systems with Bulldozer based processors consume less power than similar systems with Phenom II CPUs. However, contemporary LGA1155 systems from Intel still consume the least power of all.

In case of single-threaded load the power consumption of Socket AM3+ system rapidly increases, which most likely happens because highly aggressive Turbo Core technology. Intel base systems do not demonstrate anything like that and they can again boast much better energy-efficiency.

In case of heavy multi-threaded load things do not really change much. The only difference is that the LGA1366 system with Core i7-990X inside dashed forward. Otherwise, things are exactly the same. FX-8150 can’t boast any specific power-saving success. It does consume a little less than Phenom II X6 1100T, but Intel Sandy Bridge processors are still at least 1.5 times more energy-efficient.

AMD used all the energy-efficiency they gained from the new microarchitecture to increase the clock speeds. And in the end there is principally significant improvement neither in energy-efficiency nor in performance. Therefore, in the performance-per-watt aspect the new Bulldozer, just like its predecessors, is still seriously behind the competing Intel microarchitectures.

For your reference here are the power consumption readings from the isolated CPU and mainboard power rails:

The “pure” power consumption of the eight-core FX-8150 is about twice as high as that of Sandy Bridge processors. Since all of them are manufactured using the same production process and have similar core voltage, it becomes extremely interesting what exactly AMD meant by the energy-efficiency of their Bulldozer microarchitecture.

 
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