I agree with Dazz, fans disrupt airflow, if they are blowing in the wrong direction. I found that if the 80 mm fan is blowing air to the back of the board, right behind the CPU socket that disrupts air flow, it needs to be blowing out in line with overall air flow in the case; this reduces my CPU temp by 3 Celsius. Try it Dazz and see if it makes a difference. Considering your using a D14 and I’m only using a Xigmatek Dark Knight I would expect a 5 Celsius improvement in line with the reviews I have read (The D14 is my upgrade list for this year).
If air is blowing in the right direction, you do not need a lot of it. Inside your case needs to be like catching a chill from sitting in a drafty room because someone left a window slightly open. According to Speed Fan my average speed of each fan is only 550 rpm because their connection to the MB cool n’ quite that is why my machine is very quiet and still runs cool overclocked.
Dazz have you tried your machine without the 120mm rear fan? I heard that it can it can hamper the performance of the D14 by interrupting its air flow.
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