Does light strobing work well when ~3 fps below ref. rate?

[flaviowolff]

Hello, all!

Simple question: should I apply the method discussed on G-Sync 101 article (cap to 3fps below refresh rate) when also using light strobing?

Reason I'm asking is because the light strobing article from blurbusters recommend that the FPS should match the refresh rate.

So, is a fps just below refresh rate enough to ruin light strobing?

My scenario: Samsung 24FG70 144hz Freesync + Vega 56, of course assuming games that can run at a steady ~141 fps.

Thank you all in advance!

[RealNC]

The g-sync 101 guide should not be used when not using g-sync or freesync. You're using strobing, so that means you're not using freesync, since it's not possible to use strobing and freesync at the same time.

If you cap to 3FPS below your max refresh when not using freesync, you will get a couple stutters per second. The stutter frequency increases the lower the cap gets.

If you don't like this stutter, you should probably cap to -0.01FPS below refresh rate. You need to find out your actual refresh rate in order to do this (it's most probably not exactly 144.00Hz.) Follow this guide:

https://forums.guru3d.com/threads/the-t ... st-5380262

So when using strobing, you can cap 0.01FPS below refresh. When using freesync instead of strobing, you can cap to 3FPS below the upper freesync range.

[flaviowolff]

The g-sync 101 guide should not be used when not using g-sync or freesync. You're using strobing, so that means you're not using freesync, since it's not possible to use strobing and freesync at the same time.

If you cap to 3FPS below your max refresh when not using freesync, you will get a couple stutters per second. The stutter frequency increases the lower the cap gets.

If you don't like this stutter, you should probably cap to -0.01FPS below refresh rate. You need to find out your actual refresh rate in order to do this (it's most probably not exactly 144.00Hz.) Follow this guide:

https://forums.guru3d.com/threads/the-t ... st-5380262

So when using strobing, you can cap 0.01FPS below refresh. When using freesync instead of strobing, you can cap to 3FPS below the upper freesync range.

forgive me, I totally forgot that freesync doesnt work with strobing.
so, seems like the most desirable scenario would be constant 0.01fps below refresh + strobing, and freesync 3fps below refresh without strobing if the system cant keep up with the FPS. Is this right?

[RealNC]

forgive me, I totally forgot that freesync doesnt work with strobing.
so, seems like the most desirable scenario would be constant 0.01fps below refresh + strobing, and freesync 3fps below refresh without strobing if the system cant keep up with the FPS. Is this right?

Yep. Or you can use a lower refresh rate for strobing. 100Hz or 85Hz for example. It's really just preference. Use whatever feels and looks best to you.

[flaviowolff]

For the sake of curiosity, I reduced to 120hz and activated strobing, thus disabling freesync, limited the fps -0.007 below real refresh rate (as measured by vsynctester.com), and I got very noticeable tearing even at steady 120fps.

I only tested with fortnite, tho.

Could it be uneven frametimes due to Cpu usage?

[Chief Blur Buster]

For the sake of curiosity, I reduced to 120hz and activated strobing, thus disabling freesync, limited the fps -0.007 below real refresh rate (as measured by vsynctester.com), and I got very noticeable tearing even at steady 120fps.

I only tested with fortnite, tho.

Could it be uneven frametimes due to Cpu usage?

You should not combine strobing and "3fps below".
Purpose of framerate capping below is applicable only to FreeSync/GSYNC.

You must have zero differential for good smooth strobing without tearing & stutter

You may be required to accept a little input lag for perfect-motion strobing with zero tearing and zero stutter. Pick your poison.

However, a great compromise: You should try the new RTSS scanline framecapping feature and match the framerate perfectly with refresh rate. Basically a low-lag VSYNC ON (tearingless VSYNC OFF). I'd suggest an approximately "-50" offset and tweak up/down depending on where the tearlines appear.

[RealNC]

For the sake of curiosity, I reduced to 120hz and activated strobing, thus disabling freesync, limited the fps -0.007 below real refresh rate (as measured by vsynctester.com), and I got very noticeable tearing even at steady 120fps.

I only tested with fortnite, tho.

Could it be uneven frametimes due to Cpu usage?

You need to enable vsync. The -0.01FPS cap method is used to reduce vsync latency.

If you don't use vsync, then what you need is as much FPS as you can get. 300, 400, the higher the better.

If you have a monster GPU, you might try the scanline sync mode of RTSS, as Chief suggested. However, this really is a sync method that requires a very fast GPU. I'm not sure if any GPU out there can do that for 120FPS right now, unless you play at the lowest resolution possible and/or with graphics set to lowest. But it might be worth a try.

[flaviowolff]

Thank you both

Here comes the summing up question.

Consider two options:
a) cap to exact fps with vsync disabled, or
b) enable low-lag vsync on (-0.007 via rtss)

So,

1) When using light strobing @ 120 Hz on constant 120fps (games like CSGO, Dota, etc), which would be best, a) or b)?

2) When using light strobing @ 120 Hz on games that can keep 120fps most of the time (fortnite, COD, etc), but drops down to around 90 or 100 FPS from time to time, which would be best, a) or b)?

Thank you so much,

[Chief Blur Buster]

You need to enable vsync. The -0.01FPS cap method is used to reduce vsync latency.

Or use the new scanline capping feature.

Low-Lag VSYNC ON, Method #1
http://www.blurbusters.com/howto-low-lag-vsync-on
- Must turn VSYNC ON
- Must cap a tiny differental below Hz (fractional)

Low-Lag VSYNC ON, Method #2
- A tearingless VSYNC OFF trick
- New RTSS scan-line frame capping feature to steer tearline above/below edge of screen.
- Can yield perfect match of framerate to Hz, with low lag
- Works more reliably if you have GPU headroom

The new method is not yet a Blur Busters article, but can be superior for some games.

[Chief Blur Buster]

a) cap to exact fps with vsync disabled, or

Don't use the game capper or RTSS normal capping. It increases lag.
Instead, use the new RTSS scanline capping with an approximately -50 offset to do this.

b) enable low-lag vsync on (-0.007 via rtss)

This is the already documented method at HOWTO: Low-Lag VSYNC ON

1) When using light strobing @ 120 Hz on constant 120fps (games like CSGO, Dota, etc), which would be best, a) or b)?

(a) is harder to be reliable but can produce better results for certain games; basically low-lag VSYNC ON with a perfect framerate match.
(b) is easier to be reliable in a wider range of games

2) When using light strobing @ 120 Hz on games that can keep 120fps most of the time (fortnite, COD, etc), but drops down to around 90 or 100 FPS from time to time, which would be best, a) or b)?

Approach (a) will show tearing and approach (b) will show severe stutters during framerate dips.
If you are prioritizing on permanent motion quality (e.g. solo gameplay where you want perfect strobed motion all the time), reduce your refresh rate to cover the valleys. e.g. 100Hz strobed mode. But don't bother doing this if it's usually running at full framerate, the drawbacks of a lower Hz will outweigh the occasional inconvenience of occasional framerate slowdowns at 120Hz.