Affordable and future-proof with defects

Bought with the board about 4 months ago and I must say for the price it is offered for almost none, I think!
For me at least until last about 1 month funzte everything perfect. Then I bought a new graphics card (the GTX460 AMP by Zotac)
This probably seems a bit too hard to be oderso, anyway '' depends '' she soein little bit, with the result that the image flickers slightly.
Any idea how I can fix this, I have not but disturb it already does me something. Particularly noticeable makes the images appear dark. - For me at least.
Whether it's just a production error, or whether it is the case with all major Grakas, I can not say. But long term, I do not want to live with it and will probably soon be time to inform me closer.
But as far as a very good product.