frame sync

I have been having lots of issues with screen stuttering I believe, with my rtx 2070 and my non g sync monitor turns out to not work together because when you dont have frame sync with a monitor, you will get screen stuttering, tearing, etc. when under 144fps for my problem, since my monitor is...

In looking to upgrade my r9 280 to either a gtx 1060 or a rx 480 which should I get for 1080p gaming at max settings. I've heard and warched reviews that said the rx 480 is more future proofed for dx12 and Vulcan but is not as powerful as the 1060 in dx11. I just need a bit of help deciding. Thanks.