Correct, correct.bkragnarok wrote:When I use VSYNC OFF the tear line has to be below the edge of the screen in the VBI, right?
But if I want to combine FAST Sync+S-Sync, the tear line has to be above the edge of the screen so that it never touches the VBI, right?
You do need headroom.
For VSYNC OFF, you want the tearline deeper into the VBI so that any tearline-jitter stays mostly inside the VBI.
For the other sync methods (pre-calibrating using VSYNC OFF before switching to Fast Sync or Enhanced Sync), you want the tearline semi-permanently (99.9%) above the bottom edge. You can usually never hit perfect 100% but for many low-GPU games you can pretty much adjust it so that tearlines stay where they are 99%-99.9% of the time.
Aim for all but your 0.1%. It'll be your 0.1% frametimes that's the biggest problem such as disk-loading stutters and whatnot. The 0.1% frametime spikes will be when you get unavoidable tearing (for VSYNC OFF + RTSS Scanline Sync) or unavoidable stutter (for RTSS Scanline Sync + Enhance Sync / Fast Sync)
The easiest is simply to use the hotkeys to recalibrate the tearline position and then try strafing left/right (or doing a scroll), to find where the tearline is and how it jitters. Adjust until satisfied. Then commit to the sync mode you're planning to use (VSYNC OFF or if you're switching to Fast Sync / Enhanced Sync).