Is it normal for the wattage to slowly increase the longer you run the miners. And is it normal for the wattage to go up and down in a range and not a constant rate. This happens on all algos but for ZEC it will start around 540 watts go between say 580 and 540 then range will slowly will go over 600 watts. My PSU is 600w EVGA bronze which  I is why I'm concerned. Is this normal or is there something wrong. Also is 550 to 600 watts normal for 3 470's, seems high.