Actually, I noticed much quieter fans since the firmware update.
When I used to run GPU-intensive applications (OpenCL), the fans used to spin up to 6200rpm, but now with the new firmware update, it seems to throttle down the GPU instead of speeding up fans. 😵
(This can actually be tested with a bitcoin miner; 6750M on the old firmware could go up to 59000 mhash/s, but now it can only peak at 54000 mhash/s. I tried to keep all factors under control, but its roughly like this. Its a big enough difference to be noticeable.)
Or it could just be me. 😛