See the fan depends on the radiator thickness and fin density.
Thick Rad + Thick Fins – A lot of area to cover plus a needs to be pushed through dense fins. Needs higher static pressure fans.
Thick Rad + Thin Fins – A lot of area to cover but not much resistance, medium static pressure fans.
Thin Rad + Thick Fins – Not much area to cover but dense fins. Medium static pressure fans.
Thin Rad + Thin Fins – Worst case scenario. Medium static pressure fans, higher RPM etc.
RPM comes into factor when you need to decide how quickly you need heat to be dissipated. But, keep in mind that higher RPM means higher noise. Most higher RPM Sanyo Denki/Yate Loon and Scythe fans are screaming loud. So pretty much it comes to your call on deciding which fans to buy. Faster RPM also does not indicate better performance when it comes to radiator cooling, Always check CFM rating or H2O/m3 ratings (static pressure, in layman’s terms) to find out which fan will suit your setting the most. With a thick radiator you can get away with lower RPM fans since it takes quite a while for the liquid to get heated on those huge surface area but the case is opposite with thin rads.
Head over to Martin Squidoo’s Lab website for Fan comparison. He has done the most extensive review on radiator fans that I have ever seen.
sadinenisreeram 
May 28, 2013 at 12:55 pm
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