Game stutters when playing at higher than 60FPS

GPU MSI Suprim X 3080 Ti 12GB, CPU Ryzen 9 5900X, 64GB 3600CL16 RAM.

I had a 60Hz Asus monitor, and was happy playing FH5 at 60FPS with Extreme settings.
Due to the monitor failing I bought a new LG Ultragear monitor with 144Hz refresh, G-Sync etc.

I can play the game at 60FPS like before with no problems, but as soon as I play at a higher frame rate I get lots of stuttering - mostly in Freeroam when I hit fences, signposts etc. It’s not so bad when in actual event, in fact I barely notice it then.

I’ve tried lots of different settings, such as Unlocked framerate, V-Sync on/off, lowering the resolution and quality but it makes no difference. Even at fixed framerate of 72 there is some stuttering.

I’ve tried a lot of the fixes and suggestions posted on various forums.

are u using a hdmi cable or display port cable that is crap? i had this happen with a crappy hdmi cable

It was the HDMI cable supplied with the monitor, but I also had problems using the DP cable.
Due to some other issues the monitor was returned.