You don't necessarily want all that whizzy crap turned on to make a representative test. When I'm really trying to get work done on my computer, I turn off all that silly stuff, no matter what OS I'm running, even on my high-powered desktop. It's also not representative to run a test with the CPU at 100%. Nobody actually works with their laptop running flat out. Most laptops get really loud, hot and unpleasant when you run them like that. Like I said earlier, I like the DVD movie benchmark because it runs the screen, the GPU, the DVD drive, and a relatively small amount of CPU. It's also a very easy test to run.
Originally Posted by ikaruga
Why are you obsessed with accuracy?
Originally Posted by narf
We're not sending robots to mars here, just trying to get a bit of objectivity into OS efficiency.
Test the ammeter by seeing how accurate it's battery life predictions are, that'll rule out "wildly inaccurate" easy enough.
If it can tell me that one kernel/config/whatever is using less juice than another then it's good enough, certainly not worth ripping batteries up for.
1. Use a dead battery. You can get them on eBay.
Originally Posted by lewis
2. The current sensors they use in laptops are not designed to be accurate, they are designed to give some guidance to the power saving system. Your average DVM has a much better circuit.
3. If you want to break down your testing and try to see where individual components of the power usage are coming from, you'll want an accurate current measurement.
4. If you use a repeatable, constant load test, you wear the battery all the way down, and you have some faith in the battery's specifications, you can use some math instead of an ammeter and bypass the whole current measuring process.
5. If you really want to know where the power is going, you should determine the efficiency of the charging circuit, and you'll need a meter for that.
If you want answers that you have some confidence in and feel good about defending, then you should back them up with proper testing procedure. Don't let people accuse you of being sloppy.
Ok, you do that, that sounds like the basis of an article, meanwhile I'll scratch up a script to collect similar data from acpi on any laptop and an OO spreadsheet to graph it, who knows, maybe it'll be useful or sumfink.