MacOS – Max OS X: White saturation is terrible

i have a Problem. Here's my story: I bought a new LCD-Monitor: Acer S235HLBbmii.
I had Windows 8 till today. The colors with windows (and this monitor) were very good. All tests on this website are very good:
http://www.lagom.nl/lcd-test/

Now i connected my new Apple Mac Mini (2012, quadcore 2.3 GHz) to this display. And what can i say? The colors are very terrible.

I tried Mac OS X color calibration, different modes/settings in the OSD menu and the Windows 7 Color Profile (ICM) from the Acer website.

This test especially is just worst: http://www.lagom.nl/lcd-test/white.php
It shows me the first block (200). I can't see any other. So you can imagine that bright pictures with a lot of white amount looks very shitty.

Switching back to Windows 8 isn't considerable so i need to get this fixed.

Here is a link: https://www.dropbox.com/s/pf667jgx2idz4sl/Foto%2005.02.13%2020%2012%2043.jpg

P.S.: I downloaded and installed all updates. Monitor is connected via HDMI 1.4 Cable (good quality) and also i tried the old DVI to HDMI-Cable (which powered the display under windows) with the adapter that was shipped. Not a single improvment.

P.S.S.: Tested video out on my 27 inch Yamakasi, the white saturation is near the same. It's crap. It's oviously a software fault. What can i do to fix this? 🙁

You are my last ressort and any help is very appreciated!