Hmmmm, so you notice no noise changes from any fans at all?
Have you monitored how the frequencies work out with for example rivatuner?
Are the voltages stable?
Do you have an electronic thermometer?
The most likely result I would come up with, is that your card has a progressive fan speed controller curve, that is triggered earlier, when you OC.
Other than that, I would assume that your OC didn't work correctly.
At last I would assume you were using the wrong tools and your temps are actually BS, should none of the other options be wrong.
Sounds like an unorthodox issue though, those numbers are very implausible.
You are double checking everything now anyways, but be careful to not ruin your card and try to confirm the temps manually, instead of trusting the sensors.
