Do you have a reference design card or the triple fan windforce? I remember to have seen a youtube report for a reference design card where the guy drilled a hole into the fan and applied some oil there. Not sure if that's really necessary though.
I have two gigabyte windforce gtx 970 cards, but don't want to touch them as they run really well.
For the HD 7950s, I always remove the three screws before disassembling the fan (in contrast to the guide above). Found it easier to handle this way, and the fans sometimes sit really tightly. If you do it make sure 1) not to break the fan blades, 2) not to damage the fan power cable, and 3) not to injure yourself.
I am gonna try another oil today, as the mineral oil I used before did not yield optimal results at high fan speeds (still some very minor grinding noise, but I want it to be perfect). Got an oil from a friend which he uses for his bikes.
