First here is my Setup:
CPU: Intel i7-4790K
Mainboard: Asus Z97-Pro
RAM: Corsair Vengeance DDR3 2133 MHz CL 9
GPU: Radeon RX 5700 XT
Power Supply: Corsair RM650i
I bought the new RX 5700 XT, and i like it. But the stock cooler obviously isn't that great. But I still had the Rajintek Morpheus cooler equiped with two Noisblocker eLoop B12-P from my old R9 290X. So i swapped the cooler and it works well.
But I have problems using a custom fan speed curve.
The morpheus holds the gpu at 60°C with ease. So that is the point where I want the fans to spin with the appropriate speed to cool the memory and VRM. I want it to stay at about 1400-1500 rpm. That would be ~30% PWM because the card gets a bit whacky here and reaches max rpm of the fans at about 40%, wich would equal 2000 rpm.
So I adjusted the fan curve in wattman to sit at 30% at 60°C. When I start a game or benchmark, the fans beginn spinning higher and reach the desired rpm. But after about 4-5 minutes the card beginns zu slow them down in 1% steps, so they slow down to their lowest rpm state (800 rpm). As a result the card gets hotter and especially the memory sensor reaches over 95°C because of that.
That was with the driver version 19.7.1. I tried 19.7.2 and at first it seemed to help, but it just took a little bit longer till the slowdown started.