mazchazo :
best cfm per noise level belongs to Noctua fans. I was just wondering if 2 noctua nf-f12 PWM fans in 1200 rpm on a hyper 212 evo (push-pull config) will cover 80%-85% cpu load.
There's no way to know that until you actually try it.
Regarding the Cooler Master Hyper 212+ the only thing the EVO model brought to the table is a better contacting base and because of the base in some cases it would perform maybe 1c better.
Even though Cooler Master supplies an extra set of clips, no matter what fans you slap on it you may get another 1c cooling improvement even adding a 2nd fan.
If Cooler Master knew a 2nd fan would yield appreciable gains don't you think they would have supplied it with the cooler, Cooler Master is well aware that the fan supplied is just about all the performance you're going to get from that heat sink design.
It has everything to do with airflow over the cooling fins having the time to transfer the heat to the air, if you wanted to go for a heat pipe cooler that would benefit from a specific fan combination, you should have spent more than 30 dollars and bought a better cooler.
Coolers like the TRUE (Thermalright Ultra Extreme) a passive cooler design, could actually be used with no fans and showed major benefits with any fan combinations simply because it could cool with just case airflow, so the important thing is what is the cooler you're using capable of doing in the first place.
The Noctua NH-D14 can also be used as a passive cooler, and it can seriously benefit by a fan change out to higher cooling performance, but not fans from Noctua to gain the higher performance.
However you're seeking performance at lower noise levels, you want the best of performance with the least amount of noise, I suggest you either water cool, or get a Noctua NH-D14 and only run the 140mm fan.
Remember, you get what you pay for, you buy a 30 dollar cooler you get 30 dollars of cooling, no matter how many fans you hang off of it. Ryan