Hello, I just upgraded my GPU to reference 7970 GHz, but I noticed weird electrical buzz coming from the card under idle mode 300/150, it is noticeable while browsing, scrolling up and down. If I put the card under little load to bump the clocks to 1050/1500, the buzz disappears completely. When the card clocks drop again to idle mode, the electrical buzz is back. It is only noticeable when the case is open. Is that normal for this cards?