Doesn't happen here. Only for CPU AFAIK.
Happens on both my main rig with its GTX770, and the kids' rig with a GTX570. Both run full bore until drivers are loaded and then both go down to predefined settings (either drivers or software like EVGA Precision). My HD5870 was the same way as well. Some cards though (none that I own) do run lower RPMS though, but that is usually attributed to how the card handles itself out of driver/software control or the fans used for cooling for actual noise output.
@OP
Also depending on the fan speed profile, it might not be a smooth RPM drop and more-so an incremental speed drop...for example going from 100% to 85% to 75% to 50%...etc..etc..
Your image shows GPU clock speeds, jumping up to full 3D clocks and also shows 0RPM for the fan speed (the graph just above the GPU clocks). That shouldn't be the case. Also I see your GPU temps are being reported pretty steady at 32C, which doesn't seem to change much with full clocks.
Makes me wonder if the fan speed profile is based on GPU load and not temps?
Have you tried a clean reloading of drivers? What driver version are you running or have tried?
Something is definitely odd here, and I have partial suspect to an issue with the card itself...but at the same time a bugged driver...bugged BIOS. I would contact ASUS support on this issue after reloading drivers, software, even removing and reseating the card just for kicks to narrow everything an end-user can try to resolve an issue with before requesting RMA.
Edit: I misread the GPU clock for the Fan Speed RPM entry...with nothing else showing any reason for this.
I would wonder again if there is a driver issue, configuration issue with another piece of software, or a firmware issue with the card...my inquiries for drivers uses, etc. still remain.