Cooling GPU in a rig I don't know if this is the correct forum for asking this kind question please let me know. Anyway, I have a small rig with two GPUs (SAPPHIRE Pulse Radeon RX 580 8G GDDR5 Dual HDMI/DVI-D/Dual DP Graphics Card), the GPU temperature is running at 74℃, the inboard fans are running in AUTO at 20%, I have two external fans that I would like to use to cool it. My question is where should I position the fans? in front, back, below or uppers side  of the GPU? The back side where the name of the GPU is, is the hottest part of the device, I am afraid to set the external fans in an incorrect position and make the inboard fans workload. Any help is more than welcome.
use msi afterburner, set your gpu fans to 80% and TDP 70% then play around with core clock and memory clock, maybe +100/+450 is a good place to start

this will give you better cooling, lower power costs and better hash rates