Originally Posted by captain_clayman
right right, hot air rises, i've passed elementary school and watched the weather channel
i think i just need to get some better fans with higher "CFM" (what does that even mean? all these acronyms i dont know.
CFM is "Cubic Feet per Minute". It's a measure of the volume of air that a fan will move in that period of time.
One thing to keep in mind is not to get sucked into the "cult of CFM". CFM is not the only important characteristic you need to look for. With case fans, all that really matters is the amount of air you can move, since they're moving air into and out of a big open space with very little resistance. With heat-sink and radiator fans, you also need to have a fan with a high Static Pressure.
Static Pressure is the force of the air, measured in mm of H20. Fans with a very high CFM often have a low SP. This means that they are moving a lot of air, but once the air encounters a surface with a lot of resistance, the air will "stall" the fan; that is, it will create back-pressure and turbulence, causing the air to circulate around the fan blades instead of being pushed forward by them.
Radiators have a lot of resistance (for what should be obvious reasons); and require more force to push air through them. A fan with high CFM but low SP may still be pushing a lot of air; but it's going to end up pushing much of it around in circles, rather than through the radiator. A fan with a lower CFM but a high SP will actually push more air through the radiator, and thus greatly improve cooling efficiency.
A high SP is probably not quite as critical with a narrow rad like the H50, as it would be with a bigger rad like the H70 or higher-end custom-build rads; but it's still an important factor in maximizing cooling. Especially if you have a consistently high ambient temperature.