psu calculators

http://www.vbutils.com/power.asp
http://www.schrockinnovations.com/powercalc.php
http://www.zippy.com.tw/P_Budget.asp?lv_rfnbr=2

would have thought 400 would just have coped .. but if its old then might be low..
i got some value psu's .. just as a standby... not worth it as they are ok for short periods but not for prolonged use... kept watching the voltage levels rise and fall
spent out on a £45 one and the voltages are rock stable also feels twice as heavy