before this mobo i had a very old psu without 8 pins and 6 pins of motherboard ....it had 4 pins for motherboard (the pins near the cpu fan)
if i use it to power the mobo will it destroy something??? (without gpu)
I recommend using this PSU calculator: http://www.coolermaster.com/power-supply-calculator/ It's good because it takes into account thing like your fans.