Input Lag: Impact of Front Porch, Sync Porch, Back Porch, Blanking, Total, and Sync Polarity Settings

[m2or]

Stumbled across this thread and was wondering if these settings have any effect on input lag at all, I tried to lower and I don't understand what is better minimum timings, or VT (QFT), I want to find out which of these has the lowest latency.

[RealNC]

Stumbled across this thread and was wondering if these settings have any effect on input lag at all, I tried to lower and I don't understand what is better minimum timings, or VT (QFT), I want to find out which of these has the lowest latency.

QFT. Minimum timings don't accelerate the scanout, and thus don't affect input lag. QFT does.

[m2or]

Stumbled across this thread and was wondering if these settings have any effect on input lag at all, I tried to lower and I don't understand what is better minimum timings, or VT (QFT), I want to find out which of these has the lowest latency.

QFT. Minimum timings don't accelerate the scanout, and thus don't affect input lag. QFT does.

To get the lowest latency I need to lower the horizontal total, or raise it?

[RealNC]

To get the lowest latency I need to lower the horizontal total, or raise it?

Horizontal total doesn't matter. Only vertical total does. The higher the VT, the lower the latency. So if lowering HT allows you to use a higher VT, then just do that.

However, with that being said, don't expect any significant improvements in latency with QFT. When you run your display at its maximum refresh rate, you're already using close to the maximum VT the display can handle anyway. QFT is mostly useful when you want to run your high refresh rate (like 240Hz) display at 60Hz without VRR and use QFT, giving you the scanout speed of 240Hz while running at 60Hz. And if you're using VRR (gsync/freesync), then QFT happens automatically anyway, so you don't even need to bother. Running the display at 240Hz but enabling VRR and capping game FPS to 60 will automatically result in 60Hz + QFT with a scanout speed of 240Hz.

[m2or]

To get the lowest latency I need to lower the horizontal total, or raise it?

Horizontal total doesn't matter. Only vertical total does. The higher the VT, the lower the latency. So if lowering HT allows you to use a higher VT, then just do that.

However, with that being said, don't expect any significant improvements in latency with QFT. When you run your display at its maximum refresh rate, you're already using close to the maximum VT the display can handle anyway. QFT is mostly useful when you want to run your high refresh rate (like 240Hz) display at 60Hz without VRR and use QFT, giving you the scanout speed of 240Hz while running at 60Hz. And if you're using VRR (gsync/freesync), then QFT happens automatically anyway, so you don't even need to bother. Running the display at 240Hz but enabling VRR and capping game FPS to 60 will automatically result in 60Hz + QFT with a scanout speed of 240Hz.

there must be some correct ratio? For example, "Front Poch + Sync width = Back porch" - Front Porch and Sync Width default to 116/3 and 144/4, But I only increase the vertical setting of the back porch to 393 to get a total of 1360 is this correct?