Smart reflex is the king of the land of power saving. Some people say it causes random reboots, I however have had none with its use. Yes it works with pr1.3 Battery life is increased a shitload, it is the most important thing to use to save power (besides altering your behavior). To activate edit your kernel power profile (under ~/.kernel), you will see an option in there that switches it on. With SR you will only be able to OC up to 805MHz, although I feel that is ample speed.