I still think people need to be encouraged to google certain things that could easily be worked out by themselves in seconds. You obviously want to ask forums how to build a PC and what parts to use, but when it comes to wondering say, what VRAM is, it's possibly easier to ask google.
First of all, most people Google their problems before they seek help on forums. And that is what I did. I tried many different questions just for getting the answer I needed, but there was no luck at all. And when someone post a lmgtfy I get a little pissed off. I do not post on forums just for fun, only here seeking help form other users that has the knowledge and can give me the help I need. I have never had coil whine, and not a coil whine that hammer out on my sound card. And when you posted a Gound loop, I whould have been more appreciated that you took you time to explain how it would fix the problem with the sound issue. Since you use Ground loop ur self.
try to fix clock if that doesnt fix problem try changing clocks with 1mhz (up or down depending when you will see impovement) till whine stop or is reduced at acceptable lvls.
you have ref cards right
I'm going try this later this night, and see if it's helping isolate the coil whine.
Coil whine (or choke rattle) affects almost every card these days it seems. I had a very bad Powercolor 7970 that i did RMA because of it and the replacement had coil whine too. I had 2 7970's in crossfire and they sang with lovely coil whine. I replaced that set up with a Titan and it had coil whine also! My 780ti classified can whine but it depends on load and fps (and the whine is negligible to be fair). Most folk notice coil whine when they put a water block on as the sound output from the card's fan is removed. The reason you have less coil whine when crossfire is disabled is the fact the second card is idling. Only load will cause bad coil whine and the higher the load combined with higher clocks and voltage will do it too. As will very high fps (the closing title screen in Unigine Heaven is a doozy for it).
Unfortunately there is very little you can do about the coil whine. Reference cards are by far the worst culprits.
Some people are lucky with their cards and get a card with no coil whine at all, and some are not that lucky. All I know is that coil whine is not an warranty issue, so it is hard to RMA for that kind of an issue. But I did not have coil whine when I got my cards, it came after a while, and it sucks. Listing to that whiny sound and almost sing along haha.
I have to reference card from AMD them self.
Do not double post, by the way coil whine is very common with many cards, if you had read my link properly youd understand, by the way respect the forum users here otherwise youll stop getting help from anyone here, Rcoon has some really good advice so id highly suggest using it.
Did read it twice. Yeah RCoon did come with some good advice, but lmgtfy is kind of stepping on someone's toes, especially when that person has done his job and used google before seeking help on forums. I should have been more clear in the first post I made. That I have been searching google up and down for more info.
Another note make sure the pci cards brackets are not touching the edge of the motherboard and case at same time (pretty much causes a electromagnetic/frequency bridge- past experience is what i have on that lol) card bracket should only touch case bracket mount.
I do not think the bracket is touching the MB and case at the same time, but it's easy to find out if they are. If it's touching I have some thin thermal pads I can use between them. But thanks for sharing this.
Really simple question - are you using the headphones through the front jacks on the case or the rear jacks on the motherboard? Front panel audio jacks are well known for interference and I gave up using mine for that exact reason (my heaphones plugged into the rear jacks are noise free).
No, using jacks back on the sound card.