I have just this past few hours taken delivery of and installed a Sapphire 7970. It runs fine both overclocked and at stock speeds. However, I have noticed that whilst playing both BF3 and Crysis 2 at my native resolution of 1920 x 1080 that the card gives off a small "buzzing" sound? Don't get me wrong, it's fine, there are no lock ups occuring, no BSoD's or anything that sinister, it's just that I have read on here that someone else was having similar finding's with an MSI equivalent.
I just want to know if I should be worried? Is this normal? As someone else posted that the 6990 has this issue? And it's not noticeable over the sound of the game itself, but it's nothing to do with v sync or caps whistling as I know what that sounds like as my old 9800 GX2 was a sucker for it on the Crysis EA and nVidia logo screens!!
Sometimes its a coil whine, or a capacitor buzz, its hard to explain it exactly, but is common on some cards, my cards have a slight buzzing sound when I'm playing BF3 with MSAA on , its strange but guess it can also be a sound made by the cards workload, nothing to be concerned about its quite common.