traingineer said:
dgatwood said:
Laptops and cell phones eat batteries during testing, too. Whenever you're working with software, there's a good chance you're going to have bugs that cause excessive CPU utilization. Any time the CPU is doing work, it is consuming a lot more power than when it is idle. It only takes a tiny bit of activity every few milliseconds to seriously impact power consumption by preventing the CPU from ever reaching an idle state.
Hopefully, those bugs get fixed before the thing ships, but it isn't at all uncommon to have them during development. I'd be really surprised if anything other than the CPU were responsible for the high battery drain.
Well, Intel's CPUs generally use less power than AMD's CPUs.
Intel has greater IPC (instructions per clock) than similar level AMD CPUs at the same clock speed. More complicated than that, but basically Intel CPUs of similar generation as an AMD CPU at the same clock speed will do a good bit more work than the AMD CPU does. This lets the Intel CPU do a "race to sleep", which is to say get the CPU back to it's lowest power usage state. If a bit of software keeps the CPU active, even at low levels, it ends up using quite a bit more power than it does if it can if it is in it's lowest power state (at which point it's not really doing much at all).
Like dgatwood said, a tiny bit of activity every few (or even more often) milliseconds can result in the CPU staying at a higher power state longer than it otherwise should, and using much more power than it would otherwise. Also, don't forget that when it uses more power, it's also using part of that to generate waste heat. I don't know the formula, but I believe, in general, as the power usage goes up, for the same conductor efficiency goes down and more of the power is released as waste heat, rather than getting to where the work needs to get done.