As per the title, these 3 games always lock to 60hz. For some monitors, especially those IPS ones with g-sync, you get superior response times even at something like 30 fps, when using a base refresh rate of 144hz or higher. When the monitor is actively receiving a 60hz signal and then g-syncing down to 30 fps, it exhibits much more motion blur.
As of right now, even with the Nvidia driver set to always prefer maximum refresh rate in games, these three titles with the Widescreen Fix completely ignore the driver's call for max refresh rate. Removing the fix allows the game to run in 144hz (and exclusive fullscreen too, another issue with the WS Fix but is rectified by DXVK.)
Known issue; try 3rd party fix here: https://www.pcgamingwiki.com/wiki/Grand_Theft_Auto_III#Game_uses_incorrect_refresh_rate
Thanks for the link, that does indeed solve the problem and also helps me get back to exclusive fullscreen mode. Strangely enough DXVK only works with GTA 3 but crashes on boot up in Vice City with an Exception code: 0xc0000005 so this killed two birds in one stone. I guess since this is a known issue we can close this topic. Appreciate the quick answer.
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Known issue; try 3rd party fix here: https://www.pcgamingwiki.com/wiki/Grand_Theft_Auto_III#Game_uses_incorrect_refresh_rate