So Gigabyte will shift back to Nvidia and away from ATI according to who exactly? Sources close to ATI europe deny the claim. Gigabyte won't comment for you. How reliable are your sources? Sounds a little bit like the Nvidia cuckoo clock to me...

Gigabyte told the information to its customers in Russia.
But Gigabyte from Europe denied that the company will stop making Powered by ATI products.

Given ATI's strong positions in Europe I would suggest that European GBT will continue to sell those cards.

Reliability of the news-story is high enough to be published. Especially keeping in mind the background mentioned in the news-story.