Dozinator
The noise got to me so I open up my gaming PC and pulled the GTX 760 out. Checked all screw on back side to make sure they were tight. Then flipped it over and there are 3 screws for each fan.
I found them loose. I got 1 to 2 full turns on each screw. There are 6 total. I put the GTX760 back in and started the PC. I ran SWTOR, UT2004 and Defiance on High settings.
 
No noise and I am happy again.

Nice man.

my 770 cards all started to make a loud chopping sound.  I found out that the ACX Cooler Fans are cut too close to the fan shroud.  so, when the card sags in the back after you install it, the rear fan--the one closest to the front of the computer case, starts to hit the fan shroud.  fix?  the only solution I found was to find a way to prop up the rear of the card.
 
I never had this problem before with any other card until this ACX Cooler came out.

i have terrible rattle with my 780ti. I'll try your method Superbxxx. This will be the third time i take the cooler apart and apply thermal paste  So far, none of my methods have solved the problem. The only fins that are ¨loose¨ and by that i mean, that move and look flimsy are the ones close to the rear of the card. So i hope this method works! (what a waste of TIM)

ducknukem86
Well, I want to thank Superbxxx for the fix. I used the pink non-conductive tape included in my evga 780 classy. I put some of the tape on the place shown in Superb's guide and also some between the first fin and the plastic fan guard, as there was some space there and looked like the vibration could be generated there. Now i can say most, if not all, of the rattling is gone. I'll continue running test. But i'm super happy with this fix as my pc sits right next to me on the desk.
 

I am very happy to have helped man. Enjoy your grafics card.
 
Ps: I can not open your pictures. Can you see what is happening so people see?
 

Got my first EVGA card (770) this week on a recommendation, first self-built PC, and the first thing I did was run all my fans to make sure they were quiet. At 50% and 75%+, the EVGA ACX fans have a rattle, and then I found this thread.
 
Putting my finger on the fins nearest the ports makes it better, less help but some by putting my finger on the rear fins, so that's definitely what's going on.
 
So, I'd rather not start applying tape to my new card, but also feel silly RMAing it if its a common problem.
 
Is every 770 ACX fan going to do the same thing?

just applied this fix tonight, it helped a great deal with the higher speed resonance but unfortunately it somehow moved it down to idle speed, but when i bump the fan speed up to 40%, it disappeared.  How weird.  Bad quality control or design, imo.  I plan to use aftermarket cooling eventually, but thanks to the fix in this thread it's tolerable.  Appreciate it!
 
Update:  Well it's hard to say if any of it lasted.  I was super conservative with the tape, but it seems like it's either back or worse than it was.  I don't see how tape could really fix what I found inside that thing, seemed like dozens and dozens of fins were totally loose and at the RPMs these fans spin, it's not surprising they'd make noise.  Maybe soldering or welding the things together would work better...At this point I'm hoping for some sort of aftermarket cooling solution, but it sounds like nothing fits my board.

got a gtx 760 SC acx and have the same problem at 50-55% fan speed and some other speeds
im out of thermal tape, but will get some tomorrow and will report here with pics.
i dismantled it and found some loose fins near the pcie 6+8pin power connectors
 
edit: it got better, but then i did this
hardforum.com/
showpost.php?p=1041338891&postcount=16

Hello! I've been suffering from same problem and I am thinking of applying this solution!
However, it is very hard to find thermal tape for me so I'm asking you, is the non-conductive tape that comes with box reliable enough? Will it melt? Also, can I use the thermal paste that comes with my cpu cooler (coolermaster)? I opened the syringe cap 6 months ago, did it dry out or perfectly fine for use? I also have a 4-5 years old zalman cpu thermal paste that wasn't opened, do you think it is past its shelf life? Will I damage the chip if I cleaned the residue with acetone on earswabs? I can't find alcohol related products for cleaning purposes either, it is banned in pharmacies here!

Hi jf928. You can try this fix and doing so you will apply new thermal paste that could fix your heating problems....So it could be a wiw/win situacion. Please tell us if it worked.