[FIXED] Stutters when doing 90fps cap at 60Hz

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[FIXED] Stutters when doing 90fps cap at 60Hz

Post by Chief Blur Buster » 25 Sep 2018, 18:34

[EDITOR Note: This is an expert setting. Use at own risk]
RealNC wrote:Btw, when using scanline sync, make sure vsync is disabled. If you enable vsync, scanline sync can make things worse
Unless you enable NVIDIA Fast Sync and/or AMD Enhanced Sync (ala the "low-lag" triple buffering technique) - combined with forced flushing level 2 (which consumes massive amounts of GPU, but less important for games such as Minecraft that will easily run at max framerate).

This can be slightly more forgiving than VSYNC OFF with scanline capping, if you give it a healthy negative offset (e.g. -100 or -200), bigger than you'd normally use for VSYNC OFF. That's because framebuffer flip occurs at bottom edge of previous refresh cycle (start of VBI), not top edge of next refresh cycle (end of VBI). So to use scanline capping with VSYNC ON, you need nonblocking VSYNC ON (low lag triple buffer) combined with a bigger offset. Meaning, VSYNC OFF would have a tearline hovering at near bottom edge of screen and never touching or below bottom edge of screen. That's where VSYNC OFF tearline needs to be, in order to have stable VSYNC ON (FastSync/EnhancedSync) with scanline capping, if you want to create a slightly more forgiving (but approx +0.5ms to +1ms laggier) version of scanline capping that never shows tearlines.

You do have to calibrate the offset (Ctrl+Shift+Up) until the stutters stop. You want to be at the goldilocks point of lowest lag while still smooth before stuttery. Basically if you're stuttering, Ctrl+Shift+Up till stuttering stops. If you're not stuttering, Ctrl+Shift+Down till stuttering appears, then back upwards a bit.

People recommend running framerates above refreshrate for many reasons, because Are There Advantages to Frame Rates Higher Than the Refresh Rate? .... But it won't be perfectly smooth or tearfree. You get the disadvantage of stutter.

You need proper synchronization between frame rate and refresh rate to eliminate stutters completely. And also fixing your mouse microstutters too. Properly synchronized in getting fluidity perfection with no tearing / no stutter. VSYNC ON is one method, but GSYNC/FreeSync is another method, and VSYNC OFF+RTSS scanline sync is an advanced method of getting perfect stutterfree smoothness.

TL;DR: If your priority is perfect image fluidity, you need framerates properly synchronized to refresh rates.
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