Macbook Pro vs. HP 8510W: DVD encode energy
Using my handy new WattsUp, I collected a trace of power of Katie’s Macbook Pro and compared to my work-issued HP 8510W. The HP’s thermal and power management leaves a lot to be desired, so I knew that the Macbook would be the runaway winner on this one. But it is very interesting to see the results.
While the GHz is compatible between the two processors, I believe the HP uses a Merom (older) and the Mac uses Penryn (newer). So, it would be expected that the Mac would have a more efficient processor, but I doubt that the difference between the two can be attributed to the processor alone.
One interesting thing that I noticed with the HP is that the power consumption takes a large spike down around 700 seconds. I have no idea why this is happening… but at the same time I have noticed that the encoding speed also drops, so it would seem that somehow CPU performance is being throttled back. My guess is that it has something to do with overheating, but I can’t say for sure. I even tried looking at some obvious culprits (given my unique understanding of Intel processor thermal management features), but none of them seemed to be triggering at the time of the performance reduction. Given that the performance problem appears to trigger when the CPU’s temperature is 16′C below its max (100′C), it is very likely that the problem is something related to HP’s thermal management, which by the way, leaves a lot to be desired when compared to the macbook.
| Model | Processor | RAM | Avg Watts | Energy (Watt-hours) | Cost ($0.11/KWh) |
|---|---|---|---|---|---|
| HP 8510W | Merom 2.4GHz Intel Core 2 Duo TT7700 | 3GB | 53.4 | 324 | $0.036 |
| Apple Macbook Pro | Penryn 2.4GHz Intel Core 2 Duo | 4GB | 37.3 | 149 | $0.016 |
Looking at the cost of the encoding kind of diminishes the point of the comparison, so I almost hesitate to report it. Instead, I think you should look at the watt-hours for each device. The HP requires 216% more watt-hours to accomplish the same job!! And I can tell you from personal experience that the Mac is quiet and only warm during the encode while the HP fans are on full blast (and loud!) and the machine is so overheated that it is completely unusable. I’m not a ‘mac’ person necessarily, but I fully appreciate what Apple does in terms of thermal and power management and I wish more companies would do the same.
“Looking at the cost of the encoding kind of diminishes the point of the comparison.” Really? I was kind of shocked that a real-world event like encoding a DVD has an appreciable ($0.01+) cost. Usually, energy seems to be free, moment-to-moment. I mean, sure, over time it obviously adds up to dozens of dollars. But still, to think that encoding a DVD costs 4 cents. I don’t know, I was surprised.
And as reported here, it also costs $0.04 to watch a movie… coincidence?? I think it may be some sort of law of conservation at work.