MAMEWorld Forums - Hardware - Playing >60Hz games at 4k on a FreeSync monitor (Windows)

Hi all,

I have an 32" Acer ET322QK 4k FreeSync monitor that I use to play MAME games with CRT shaders applied. Most games play very smoothly thanks to FreeSync, but I noticed that some games (such as Rally-X) still had some stuttering. I then discovered that these games all have refresh rates of 60.6Hz, and MAME's own FPS metric showed a steady 99% of target - just short.

This is not a MAME or a FreeSync limitation; DisplayPort 1.2 itself has a limit of 60Hz at 4k. However, I found a solution for Windows:

Install Custom Resolution Utility (CRU) (https://www.monitortests.com/forum/Thread-Custom-Resolution-Utility-CRU).
In CRU, click "Edit..." to the right of the monitor name at the top, then change the maximum "V rate" value from 60 to 61.
In CRU, under "Detailed resolutions", choose the 3840x2160 resolution, click Edit, and change the refresh rate near the bottom to 61Hz.
Run the restart64 utility provided with CRU to restart your Windows graphics system.
In the Windows display control panel, change the refresh rate to 61Hz. (In Windows 10, I did this at System > Display > Display adapter properties > Monitor tab > Screen refresh rate drop-down.)
In your mame.ini file, set waitvsync to 1.