Poor Quality Image on TV plugged to Thunderbolt HDMI

Hello.

So here is the thing, i bought a mini display port to hdmi cable (a generic cable, bought at dealextreme), I plugged it in my sony bravia to my mbp late 2011.

But everything looks strange, the text is blurry and it looks really bright.

So I boot camped to windows 7, and everything was fine, the image and text was cristal clear.

Does anybody know what may be causing this problem? As i said, its a generic cable, altought everything was fine when running windows 7.

I couldnt quite formulate this question to google, so i'm sorry if this is a normal problem and there's already an answer in the community.