Having run 11.4 for about 24 hours now, I can now update my previous observation. The fan isn't always louder. It seems to be loud for an hour or so at a time and then can be quiet for many hours, then eventually gets loud again. Not sure what is up with that.
I'd imagine there is probably some sort of tool I could use to monitor and record the fan RPM and the GPU temperatures. However, I won't be going back to an older version of the drivers (since I'm upgrading to a 6990 on Monday), so this data would be in isolation as I wouldn't be able to collect similar data using the old drivers to see what the difference is.
Another difference is that the ambient temperature may be changing, since the weather is also starting to get warmer. So it may not be due to 11.4 but because we've had a 10°C change in the outdoor temperature over the past three days. The computer is in my basement, where the temperature should be relatively constant, but perhaps even a couple degrees would make enough of a difference to bring the fan to the next higher speed. Who knows. All I know is I can hear it upstairs, whereas I didn't used to be able to.
Yes you can manually set the speed in Catalyst Control Panel but you can't build profiles there as far as I know - at least not in windows and with 11.3 that I'm using. To build custom fan profiles and overclocking profiles I recommend MSI Afterburner. Btw, changing the fan speed won't cause your card to burst into flames unless you set the fan speed to low for extended period of time - but even then the card will throttle down its clock speed if it overheats.
I think what's happening with the fan getting loud and quieting down for many hours is that it has a certain thermal max target and once the temps reach that it sets the fan to super high which cools the card sufficiently to keep it steady below that thermal threshold for a while. That seems quite annoying though. I would much prefer it to be at a constant value.
Hmm, yeah that may be the case (regarding the ambient temps). You may want to make sure that there is ample air circulation in the room - ie basement. It could be that be ramping up the speed because what's happening is that the ambient air temp in your basement has been going up steadily. In other words it needs some fresh cold air - the poor thing