Hi, it's sadly common place for high end video cards to make electronic noise under heavy load, I've seen case where it also causes the PSU to squeal too! Typically under stress tests eg Furmark etc or compute loads like [email protected]
My experience is the higher-end the card the more likely it is to do it.
With PSUs there is s a lot of variation and you can get a "good one" that doesn't. More expensive/better quality helps, some models better than others but after that it's almost luck!
I had a GTX260 that was pretty bad and I more-or-less cured it with a lot of super-glue! Similarly with a GTX285 too, my current GTX560 Ti has a very high pitched squeal under [email protected]
, some units are worse than others, mostly its quiet enough to ignore. I've not tried to see if I can improve it as it's nothing like as loud as the GTX 2xx cards were.