I have a Powercolor Red Devil 5700 XT (great thing so far), an MSI B450M Mortar mainboard with a Ryzen 5 2600. I set up Windows 10 on a new SSD, so the system is clean with the latest drivers and bios.
I encountered the problem that when I use the native refresh rate of my 75hz screen (iiyama GB2730QSU-B1 WQHD), the memory clock is always at maximum speed, even in idle on desktop. Thus the fans regularly start spinning when a hot spot temperarture of 60°C is reached.
When I limit the refresh rate to 60hz, the memory down clocks as it should be and stays cool.
I attached two screenshots from GPU-Z.
I borrowed a Sapphire Nitro+ which shows the exact same symptom.
I would like to use 75hz ingame and not have to change the refresh rate everytime to have a quiet and cool card in idle and on desktop.
Maybe someone can help me or fix that behavior in future driver update. Let me know when you need some more information.
Thank you and greetings from Vienna!
Download toastyX's custom resolution utility. Using the utility, find where your 75Hz mode is defined. Click edit and change the timing from manual to LCD standard. Exit the utility and run restart64 to restart the graphics driver. Now check your memory clocks, they should be idling properly. You can run reset-all.exe to undo you changes if you want.
If you want to understand what's going on, it is described in this reddit thread.
I found an easy solution: In the Radeon software I added a "custom resolution" and only changed the hz from 75 to 74. It works for me!
Nevertheless this behavior should not happen at all...