I got my GA-MA770-DS3 mobo returned today under warranty and when I fitted my replacement CPU, a AMD Phenom 9600 x4 2.3GHz it worked perfectly.
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So thanks for the repair and the quick turn around. You're the best!
(Any one want to make me an offer for a my 'old' AMD Phenom X3 8750 2.4GHz CPU I also sent it off under warranty and got a new replacement from AMD
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).