Lower Energy Consumption : Feeling the Squeeze: AMD's Athlon 64 X2 6400 Black Edition

Tom's Hardware > Articles & reviews > Feeling the Squeeze: AMD's Athlon 64 X2 6400 Black Edition

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Lower Energy Consumption

02:16 - Monday 10 September 2007 by Bert Töpelt
Source: Tom's hardware UK – Keywords: AMD, X2, 6400
Categories: Hardware

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Lower Energy Consumption

We compared the new model’s energy consumption at 3.2 GHz with that of its predecessor at 3 GHz – with surprising results! Despite its 6.6% higher clock speed, the Athlon 64 X2 6400+ draws 2.1% less energy than the 6000+.

This is a clear indication that the 6400+ models are cherry picked – in other words, AMD has collected a number of CPUs that perform especially well. If there are a sufficient number of them, the chipmaker can then sell them under a new, higher model number – instead of actually coming out with a new processor.

So how does energy efficient is AMD’s new release compared its counterparts from Intel?

Compared to Intel’s current dual-core processors, the energy consumption of AMD’s processors can only be called frightening. Intel’s fastest dual-core processor, the Core 2 Duo E 6850, requires only half as much power as AMD’s new part. Even with twice as many cores as AMD’s 6400+, Intel’s smallest quad-core model Q6600 draws 12% less current.

We measured the processors’ power consumption on an ASUS M2N32-SLI board for AMD processors and on a Gigabyte P35C-DS3R board for Intel CPUs.

The AMD board uses an 8-phase power design, while the Intel board comes with a 6-phase design. That puts AMD at a slight disadvantage, but the difference is negligible in the face of such large differences.

It should also be clear that the fan noise is much higher in the AMD system as a result of its higher power dissipation.

Our 6400+ consumed 124 watts. If we subtract about 6 – 8 watts for the fixed voltage regulators, which also draw power, we are still left with a real-world energy consumption of 116 watts. Considering the optimizations that have doubtlessly gone into the 6400+, a 6600+ follow-up model is possible, but not very likely.