Trying to Understand G-Sync/Freesync

[av8r172 2]

I'm looking at 2 monitors. One is G-Sync compatible (48-165hz), the other has AMD Freesync premium. I have a pretty modest system, and with my settings I do dip below 30fps at heavier airports. I understand ideally, I would want a full G-sync monitor that can sync from 1-144+hz, but these are very expensive. AMD freesync premium and G-Sync compatible monitors have something called a LFC: Low Framerate Compensation, which doubles frames below the minimum refresh rate of the monitor to avoid judder/tear.

Can anybody shed light on this? Or will I not minimize frame rate fluctuation stutters unless I go for a full G-Sync chipped panel? I would like to run at 30hz, it's just almost impossible to figure out before you buy a monitor whether it will allow you to set a static 30hz refresh rate. Currently, my monitor can only refresh at 60hz. Using adaptive half refresh rate in NCP looks great and smooth, except when panning or resetting my view, which judders horribly. Trying to eliminate this.

Edited June 21, 2021 by av8r172

[Afterburner 374]

It's been a while since you opened the thread, but since I have a Freesync monitor (non-premium), I can tell you a little bit from my experience. 

Generally, a Freesync monitor should synchronize the monitor refresh rate (Hz) with the FPS of your game. This works well if the FPS don't fluctuate too much and if they are within the monitor range. If they fluctuate a lot (and they can if you set the FPS in the simulator to unlimited), the monitor may not be able to follow the changes in FPS, so that you see stuttering. For example, there is the demo software "Pendulum" by Nvidia that can be used to test if Gsync/Freesync works. This program allows you to change the FPS yourself. On my Freesync monitor, which normally runs at 60 Hz, if I change the FPS in the said program from 60 to 55, the monitor changes the refresh rate to 55 Hz. If I reduce the FPS to as low as 28, the monitor runs at double - 56 Hz (it can't go to 28 Hz). This is the nice thing about a Freesync monitor.

As I wrote, this works fine if the FPS is relatively stable. If you have even mild fluctuations, the monitor will try hard to "follow" the FPS, but it will not happen immediately, so that there will be an instantaneous mismatch between the FPS and refresh rate. For a flight simulator, I rather recommend to use a fixed refresh rate. Which simulator are you using?

[HighTowers 1,434]

All I can say is do the homework. The original freesync I have does not have LFC , so lower than 48fps goes beyond the minimum 48hz and therefore does nothing.  It is G-sync compatible though so works with my 2080ti. This article below does a nice job  of explaining the differences. 

What is also a problem is that MSFS does not support freesync at this time, so nothing native but the monitor should still try to kick in. P3D v5 now added an option called variable refresh rate , and when I turned that on, it was way smoother.  Hopefully MSFS adds it in due time. Thats why G-sync is that much better, but you definitely pay alot more for it. 

https://www.tomshardware.com/reviews/amd-freesync-monitor-glossary-definition-explained,6009.html