We had a similar post before, Its probably a transistor/capacitor resonating. Has been known to be a fan rubbing on the cover. However as it seems affected by you scrooling it would sugest electrical issues and some sort of interferance, Is your mouse wireless ? Im not an engineer but i think its possable that whatever is resonating has inadvertantly fell into sync with some other component on the PC and is causing some kind of feedback. Personally i would RMA the card.