check the dBA (decibels) rating on the fans you buy, 35 or more is kinda loud, under 25 is pretty quiet. also, teh thicker your fans, the less rpms the need to push teh same amount of air (airflow). your thin ones are proly too speedy and too noisy.
does ur case require the thinner design? if not, buy some regular 80*80*25 with a lower dba rating
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