playing with powertop on my netbook

I know that this via netbook does have issues with powermanagement and i want to digg deeper
to get some sort of power/instructions trace
so i have installed powertop

sudo apt-get install powertop
what is interesting C3 state (sleep) is buggy on this cpu (cache incoherent)
and i see that is really used , it should be disabled by bios but i know that bios is buggy too.

Powertop suggested this
echo 1500 > /proc/sys/vm/dirty_writeback_centisecs

so i have added it in /etc/rc.local
before the exit 0