Power Consumption Tests
After the mediocre results of the Athlon 64 X2 4800+ processor on the 65nm Brisbane core in our performance and overclockability tests, it is now clear that it can only prove to be superior to its predecessors in efficiency because the typical heat dissipation of every Athlon 64 X2 on the new core is 65W whereas the typical heat dissipation of CPUs on the 90nm Windsor core is 89W. However, AMD has been offering Energy Efficient processors on the 90nm Windsor core since the last half of the summer. Such CPUs have a typical heat dissipation of 65W and it’s not quite clear without additional tests how they compare with the new 65nm CPUs. So, we added an Energy Efficient Athlon 64 X2 4600+ on the 90nm Windsor core into our power consumption tests.
In these tests we use the same platform but with different CPUs. We measure the current passing through the CPU power circuit – it is indicative of the power consumption of the CPU (but without considering the efficiency of the CPU power converter). The CPU is loaded up by running S&M and Intel Thermal Analysis Tool. We activate the power-saving technologies AMD Cool’n’Quiet and Enhanced Intel SpeedStep for the test. Here are the results:
It’s interesting: the Intel Core 2 Duo E6400 is more economical than AMD’s solutions under full load but consumes more power when idle. Comparing AMD’s CPUs, the 65nm model seems to provide a better performance-per-watt ratio than the ordinary Athlon 64 X2, but the Energy Efficient Athlon 64 X2 4600+ consumes less than the new CPU under full load.
So, AMD’s new CPUs aren’t so much better than the older ones in their energy-related characteristics. AMD has already managed to achieve the same power consumption with the older Windsor core. We must acknowledge, though, that they had to cull dies capable of working at reduced voltage then while the new Brisbane core seems to achieve the same purpose without any special tricks. Moreover, the maximum frequency of AMD’s Energy Efficient CPUs on the Windsor core is 2.4GHz whereas the new core can work at 2.6GHz (and is expected to work at 2.8GHz in the future), having a typical heat dissipation of 65W, too.