I did a ton of research on it last week. The traditional thing gamers do it just let the GPU run 100% (no cap). I don’t like this because it wastes power and makes more noise so I like a cap, esp since the benefits past 144 are negligible.
You are correct in that, for gsync, you want to fps cap just below the refresh rate of your monitor. Otherwise gsync either goes into vsync behavior (frame buffering) or it tears after the game’s refresh rate surpasses the monitor refresh rate. FPS limiters can drift, so 2fps below is considered a safe range.
Gears only has version fixed ranges (though I put in a request for them to change that menu, hope they see that thread) so you have limited options. You can use an external limiter like RTSS, but it adds 1 frame of latency. I personally either;
-Run 120fps on a 144hz gsync monitor.
-Or overclock my monitor to 150hz and game at 144.
Gears seems to cap just below the target, for instance 143.98 instead of 144, so you might get away with just using the cap at your refresh rate. However, I didn’t feel it was as consistent or responsive when I did that. After reading about gsync it made sense.
Hopefully that helps. I’ve only been using a monitor for about a month so I’m learning as I do. I normally game on a big OLED but I now have to play lying down until my neck heals up.