The 212 is a good cooler for its price. But on the ones I installed, the base on them looked like they were finished with a beltsander. Being overly analitical, I make assumptions on how much metal to metal contact I am going to get. And in my opinion it was not going to work like I wanted.
So without wasting to much time or effort (20minutes) to perfect it, I flattened out the high ridges on it. A quickee lapping job
I put 600grit high quality metal oxide sandpaper down on a perfectally flat surface, and moved the base of the sink in the opposite direction of the ridges. Knocked down 1/2 of the ridges height. Then replaced the sandpaper with a microfiber rag, and a normal (slightly abrasive) car wax. Keeping the base perfectally flat, not taking off any more than nessisary to just knock down the high machining ridges. Once Finished it was not mirror or perfect, but it would get a lot better metal to metal contact going.
The I cleaned off all the wax and junk, (dont want any grits in there :-) cleaned it with alcohol and a tech spray. Then fully dried it , which includes the micro porosity of the metal.
Before applying thermal paste, I like to "Permiate the porosity" of the 2 metal surfaces. So I use a lint free microfiber rag, and rub the thermal paste into both surfaces, then remove most of that.
Applied AS5 thermal paste , just because that is my today favorite still and I had some. And I used the very thin spread method, because that is my choice of paste spread methods. (especially when the first seating might not be straight down) The 212 can have tracts down it because of the "touch" base , so using the Squished pea or line method just was not going to work.
Putting it on One of the computers cpus, replacing the stock intel, and its mostly dried up junk paste under it, went way over my expectations. the thermally controlled fans didn't even go past thier Idle speeds until I ran some hard stress testing, and even then it was great.
You did not say what Overclock your running on your chip, or if your at stock, and you did not indicate what Voltage the CPU is at?
When it comes to IDLE temperatures, you did not indicate how you have the bios set to allow things Like CE states , and all the other cooling and power saving features. Some features of the bios can put the chip into a very low power state. Even the OS your running could be "waking up" the cpu more or less, or how you have the OS set.
The way you have all of those things set, can make very big differances, when trying to compare your results to others.
Also I agree a lot with Waterwizards, pointing out that you cant get room temp CPU readings, without good case cooling and logical Flow of the air patterns via the fans and all.