Torture testing my 3570k

Hi guys,

About three months ago, I build my first rig.

The specs are the following:

Case: Fractal Design Arc Midi R2  Two silent series fans in the front and one in the back.

CPU: Intel Core i5 - 3570k.

Cooler: Be Quiet Dark Rock Pro 2.

MoBo: AsRock z77 Extreme 4.

GPU: None yet, I am using the Intel HD 4000, next month I am going to buy the real thing.

So as I am busy working and studying, I never got the time to play around and see how the rig performs.
After playing with Prime 95, CPU-Z and realtemp with the i5-3570k stock speeds, I noticed something weird.

When all my fans spin around 600 rpm, my idle temps are between 28c and 35c.
When I spin them full blast, the temps remain the same.

And when I'm using p95 small fft torture test the readings are as follows:
At 600 rpm, between 58c and 66c.
Fans at full blast also exactly the same.

What does this mean?
It looks like I can't get the temps down when spinning the fans harder.
Also is 66c on full load not a bit high on stock speeds with the big be quiet cooler?
Is that normal? Or is there something I should look at?

Thanks in advance!