G-Sync & FreeSync: The Problems Nobody Talks About

Summary

The video explains how to optimize Variable Refresh Rate (VRR) on FreeSync and G-Sync displays, focusing on refresh-rate jumps and flicker that can occur even when the frame rate appears stable.

How VRR and LFC Behave

• VRR adjusts the monitor’s refresh rate to match the game’s frame rate while it remains within the display’s supported range.
• The presenter recommends confirming that VRR is supported and enabled in Windows, and that Windows is using the monitor’s maximum refresh rate.
• Below a monitor’s VRR range, Low Framerate Compensation (LFC) can repeat frames and raise the refresh rate to a multiple of the game’s frame rate. In the presenter’s example, a 48–120 Hz display running at 30 FPS reports 90 Hz.
• The presenter also demonstrates refresh-rate changes at frame rates within the stated VRR range. They attribute these jumps to unpredictable LFC behavior, which they say can cause refresh-rate desynchronization, stutter, or flicker. They note that the behavior may be more pronounced on higher-refresh-rate displays.
• To inspect the issue, the video uses Special K to display software-reported refresh-rate data and compares it with the game’s frame rate. The presenter cautions against using third-party tools such as Special K or Frame Pacer in games with anti-cheat.

Optimization and Troubleshooting

The presenter suggests trying these steps:

1. Confirm VRR is enabled and that the monitor is set to its maximum refresh rate in Windows.
2. Cap the game’s frame rate at a level the PC can sustain. The demonstrations use RivaTuner Statistics Server (RTSS), including its “front edge sync” option.
3. Test different frame-rate limiters if the first one does not help. Options mentioned include RTSS, Special K’s limiters, Frame Pacer, and GPU-driver features such as AMD Radeon Chill and target frame rate control. The presenter describes AMD’s target frame rate control as especially forceful, but with latency close to V-Sync.
4. Reduce the monitor’s maximum refresh rate if LFC-related jumps persist. For example, when targeting 60 FPS, limiting the display to 75 or 100 Hz may reduce the chance of a refresh-rate doubling.
5. Turn VRR off as a last resort if the display remains unstable. The presenter notes that this may be less costly on very high-refresh-rate monitors.

The presenter is critical of LFC, arguing that its benefits can be outweighed by erratic behavior. They also say the PlayStation 5 does not use LFC in the same way: in their account, 40 FPS requires a 120 Hz mode.

Sources

• Main speaker: Hardware Accent channel host, demonstrating settings and test results.
• Additional sources: Community members who shared VRR results and optimization advice.