I observerd interesting things here are some.
Under "developer options" toggle -> show cpu usage
Then you can see what process is top most, gsiff will be second from top if it's running. Not sure if it has anything to do with motion sensor. If you restart phone gsiff should be gone, and toggling motion sense options will not bring it back. At least on my stock att rom.
When gsiff is ON, cpu will not toggle off second core, to me it looks like it gets stuck in some kind of mode. Benchmark scores will be lower especially easy to see on linpack multi thread test instead of ~200mflops you get 90ish, possibly indicating single core performance. But some things are better, ui seems more fluid, and media playback I can play HD 60FPS high bit rate videos. This is important as I'm media fanatic.
If gsiff is NOT RUNNING one cpu core will turn off and other clock down to 384mhz entering proper operation I assume, linpack will perform normally, cpu and gpu scores will be higher, but the bad thing is media playback ability will not reach its full potential say goodbye to 60FPS playback (this sucks for me) , my guess is, it is software problem during intense media playback cpu doesn't exit special conservative mode, probably keeps decoder clocked down.
I did find one way to trigger gsiff on, with "blade buddy" app from market under advanced settings hitting menu button and selecting apply - yes ui restart.
If anyone wants to experiment.
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