Questions: GPS Power use and underclocking
 

I've got two (make that three) questions... I was recently backpacking and took along my phone to act as gps/camera, and realized that it kind of blows for this, as the battery doesn't really last long enough.

My first question: does anyone have any idea why the GPS on the Touch Pro is so power hungry? Normal backpacking GPS chips use like 10 mA, and the touch pro uses roughly 300-400 mA. I know it has to run the CPU also, but this should only increase it to like 75 or so mA, since the CPU stays at 10% usage.

And the second question: Will underclocking the Touch Pro really show any power savings? I was under the impression that power savings on the Qualcomm MSM chips is achieved by selectively turning off portions of the CPU, so instead of having the whole chip running at 528 Mhz, you'd get 10% of the processing power at 528Mhz and save a butt-ton of power. If you underclock the processor, you'd just need to use a higher percentage of the processor, so your power savings would go out the window.

Last question: after underclocking the processor and looking at the power usage of the TouchPro using AcbTaskMan, I realized that it doesn't make any sense... AcbTaskMan shows that underclocking the processor will save exactly 0 power, while still increasing the percentage CPU usage (when the screen is on, and nothing but AcbTaskMan running, the processor shows 7% usage with 57mA draw at 528 Mhz, and 12% usage with 57mA draw at 220MHz). Is there any relatively easy way to see how much power is actually being used (a utility which measures USB usage or some kind of off the shelf power meter which gives accurate results when drawing less than a watt)?

Thanks in advance for any responses.

Re: Questions: GPS Power use and underclocking
 

try undervolting it, since when you underclock it won't do jack. I just leave my processor at 528mhz but put it on the lowest voltage available. if the processor is underclocked it will still "ask" for the same high voltage...and voltage equates to power