Power Consumption Testing

Because of the importance of power and efficiency for this particular article, we are going to spend extra time with our power meter.  First up, let’s see our standard idle and load power consumption comparisons:

VIA Nano and Intel Atom Review - Battle of the Tiny CPUs - Processors 43

VIA Nano and Intel Atom Review - Battle of the Tiny CPUs - Processors 44

At idle the VIA Nano uses just about 3 watts more power but at full load that changes dramatically.  The VIA CPU spikes the system as high as 77.5 watts while the Intel Atom processor JUST crosses the 60 watt barrier.  

I also decided to use the ability for my power meter to log results to see how power consumption looked over time when comparing the VIA Nano and Intel Atom processors.  What you see below is a graph of power consumption over time.

VIA Nano and Intel Atom Review - Battle of the Tiny CPUs - Processors 45

For the first test I used our benchmark that encodes an MP3 with LAME to compare power draw.  Notice that for the blue line that represents the VIA Nano processor, you can clearly see where the processing begins: at the large jump in power consumption from about 60 watts to 77 watts or so.  The Intel Atom processor lives up to its claim of super-lower load power consumption and you almost can’t tell that the Intel platform increases power draw during the test – but it does! 

Of course as our benchmarks showed you on earlier pages, the VIA Nano CPU is definitely faster though – so how can we compare the data in this graph?  One way is to see how much energy it takes for each CPU to actually complete the work.  You might remember this theory from Intel’s Centrino 2 launch known as the “Hurry up and Get Idle” idea. 

For our MP3 encoding test, the VIA Nano processor used a total of 37,323 watt-seconds (Joules) of energy while the Intel Atom processor used 38,290 watt-seconds (Joules) of energy.  That is a difference of just 2.5% indicating that even though the Atom processor is slower, it’s not that much less efficient than VIA’s Nano.

VIA Nano and Intel Atom Review - Battle of the Tiny CPUs - Processors 46

**Note on the power supply – in our power consumption testing we should focus on the change in power consumption from idle to load – much of the total power draw will be based on the use of this rather large PSU.

Using the same method to gauge the results of our CineBench 10 test, we find that the VIA Nano used 63,434 watt-seconds (Joules) of energy to render the scene while the Intel Atom used 65,893 watt-seconds (Joules) of energy – an advantage of 3.8% to the VIA CPU.

These kinds of power comparisons are incredibly insightful and you can clearly see how both teams of CPU designers have made trade offs for the either power consumption or speed.  The VIA Nano L2100 is able to perform these tasks faster (by as much as 30% in some cases) while still using less total energy than Intel’s Atom.

« PreviousNext »