And of course install 15.12 or its dll-s at least.
I saw many times that 15.12 is the best, but no real evidence. I tried both 15.12 and latest 16.5.1 on my rig with few different cards (7950, 7970, 390X) and saw no performance loss/gain. What exactly is wrong with 16.* apart from they use different software architecture inside?