Hello I have a late 2009 iMac system running under El Captain OS. I have noticed the fan(s) spinning too fast, encountered screen flickering dark a few times and I checked with this app smcFanControl and this is what I got: ODD 4340-4350 rpm (variably; this is normal or abnormal?) HDD 1099-1100 rpm CPU 3797 rpm 129 degree C (264 degree F) I'm deaf, though I can feel the spinning breeze from the back of my iMac, I cannot tell how loud the spinning is. I tried SMC reset but I don't know that resolve anything. Should I update the iMac OS to Sierra?