The P55, H55, H57 power up twice becuase it is the motherboard setting the clock gen mode. With bios version A51 and later there was a option added called "ClockGen Switch Mode". Once this setting is "enabled" it will not restart the computer twice.

Please note: with this setting is "enable" it will limit the ability to overclock your CPU. If you would like to overclock, Please remember that this could VOID your processor warranty.