I think the point was a 4670k or 4770k is going to stress a stock intel fan - which is not really up for the duties demanded.
Two things happen: (Both bad)
First- The stock Intel Fan must run hard, increasing noise due to higher RPM speed.
Second, The CPU runs hotter than ideal because the stock Intel fan is limited in cooling capability.
When you upgrade the fan a couple things happens: One it can get quieter (not that Intel stock fans are super loud. They are usually quiet unless your going hard). Two, Temps can drop down.
I picked up a Coolermaster EVO2 212 air cooler at Microcenter last week for $19.99. I believe it was marked wrong, but I confirmed the price with the checkout girl. They had a pile of them at the front of the store bulked out with a sign. I believe the non EVO was supposed to be $19.99 and the EVO was $29.99 (still good value) but since it was marked wrong I bought it. I bought it as a last minute after thought much like you would add a candy bar or pack of gum at a grocery checkout. Looking back I am glad I did, because for $20 it saved me the trouble of having to remove my other after market cooler I was originally going to re-use from my 2600k machine.
My long term plan is for a water cooler, which is why I did not want to get too serious with an air cooler or spend big $$. But for $20 the EVO is a great air cooler if you can fit it.
I added a second 120mm fan so there is a fan on both sides of the large radiator.
The results are it is super quiet because most of the time it is going at very low RPM. Lower the RPM the quieter the sound. That is why a high end cooler can often be quieter and cool better than a stock cooler. It cools much better because it's like 5 times the size of the stock intel cooler with more radiator, more surface area, and two 120mm fans moving more air than a small single fan.
Disclaimer: I run a 3570k in my HTPC with stock intel cooler and it's in my bedroom and I hear nothing. No hate on Intel stock coolers. For non overclocked situations they work fine on any mid range or under CPU.