I am sitting in front of a 9860 (right) and 9750 (left/front).
Both are encoding similar jobs, 9750 is on 50C permanently, 9860 on 56C permanently. Although 9860s VGA fan is spinning low and quiet, CPU fans are definetely more noisy than the 9750s altogether.
Please note I stepped 9750s fan automatic 10 steps and 9860s 15 steps upwards. (AC2trip from 50->40 / 60->45)
If I wouldn´t do that, 9860 would be at 62C with same noise and 9750 would scratch and whistle...