VSYNC in RF2 : pros&cons / advantages-disadvantages / tips-settings

---

 

As far as I know, fast sync is only available to nVidia users.

In querying people as to whether they like fast sync, I suspect that people with adaptive sync monitors find fast sync problematic whereas those with a fixed sync monitor find fast sync very useful.

 

Where is the difference/ what does fast sync exatcly different?

 

AMD's got Enhanced Sync, which acts like Fast Sync.
https://www.tomshardware.com/news/amd-enhanced-sync-framrate-synchronization,35087.html
See fifth panel.

 

I have a 1070 and G-Sync enabled triple monitors. Up until build 1070, I’ve been running with Sync turned off in-sim and G-Sync enabled on both monitors and GPU. The monitors have a (true) FPS overlay available so you don’t have to rely on some software calculation.

It worked pretty well in 1109 - quite smooth and FPS only dropping from max occasionally. When FPS did drop, it still felt fluid.

With 1109, I immediately noticed that the image appeared ‘micro-stuttery’ - particularly noticeable with heavily wooded tracksides as you go around corners.

As an experiment, I tried turning Sync to ‘GPU’ in sim. The impact was significant - the micro stuttering was gone and the sim is silky smooth again. There was an FPS hit - which I find perplexing as I thought the whole point about G-Sync was that the monitor only refreshed at the speed the GPU could push out frames anyway....

 

Using a freesync monitor and AMD 290x I have the video settings in rf2 set to gpu sync. I get no stutter or tearing. Looks excellent.

 

Talking about sync. What does every sync option on rFactor2 does? I see like 3 different ones.

 

Game Configuration
Vsync will keep your screen from tearing, but also guarantees you will have significant display lag, to the point where you can easily see it by wiggling the steering wheel back & forth and the onscreen steering wheel movement will lag. Serious racers never use Vsync for this reason; people sensitive to eye strain & flicker often favor Vsync on their 60 Hz monitors & TVs and are more likely to not need Vsync when a vertical refresh rate above 90 Hz is chosen. Using Vsync with an adaptive sync monitor is a bad idea.

No sync effectively has no display lag, but your screen is guaranteed to tear unless your monitor has adaptive sync. You will notice the tears either as a flicker or a large vertical element out of alignment in the picture. Adaptive sync in a monitor can introduce some lag and/or stutter when it is rapidly changing refresh frequencies (e.g. sudden fps drops/gains), but it is usually considered to be imperceptible.

GPU Sync... er, I can't remember exactly how it works, but I believe it requires the graphics programmer to find the times to write blocks of frames into the frame buffer without causing tearing. I don't know if it introduces display lag. As I recall from trying it out, display fps is lowered because the program can't write to the screen whenever it wants to and there's probably a stutter effect if the fps falls below 60. NVidia supported the method long ago (before 2010?).

Video Driver Configuration
Fast Sync (nVidia 2015+) & Enhanced Sync (AMD 2017+) are hardware buffers enabled in the video driver (with the game set to No sync) that may occasionally tear when fps falls too low, but does not require the monitor to have adaptive sync hardware. Often described as Vsync done right. May cause stutters on adaptive sync monitors if the refresh rate is not locked (or it may not...I need some adaptive sync monitors to test sometime).

Selecting a good sync option is tied to the fps your system can provide and the vertical refresh capabilities of your monitor. If your system can only provide 40 fps as a minimum with a field of cars even on the lowest graphic settings, then the best results will be obtained with an adaptive sync monitor. If your minimum fps is above 60 fps, then you have more options.

 

I appreciate your response @Emery , I already know about vsync, no vsync, free sync, fast sync and adaptive sync, which some are related to specific hardware vender. I am asking about the options that comes on the rFactor2 config settings. Which are Software, GPU and Video.

Is there a wiki page or something where all this settings are explained? To be honest it bothers me the lack of documentation of these and the other graphics settings and their impact.

 

From https://web.archive.org/web/20120607021034/http://isiforums.net/f/showthread.php/1396-Downloads-(Installer-ISI-cars-tracks-Templates)?p=47806&viewfull=1#post47806 :

A note about driver, Fast and Enhanced, synchronization: you should get a tear free video if your hardware is capable of rendering frames faster than your monitor refresh rate. It has much less lag compared to traditional vertical synchronization. At the cost that your hardware will work at its maximum, so expect high temperatures and power consumption.

 

For the first time in 12 years of simulation RF1 and RF2, I decided to stop the VSYNC.

My minimum FPS are :

- Worst conditions :
Rain, clouds, sunrise, timescale X15, 30 AI, mirrors, headlights, etc.):

Minimum 24 FPS but rather under these conditions 40 FPS.

- Optimal conditions :
Official track, official car, day, 30 AI, cloudy, etc. :

FPS minimal = 216.

Please advise me :

I want a very low input lag, but, if the fast sync really brings very little input lag compared to without any vsync, then is it a good idea to activate it to lessen the eyes ?

If the input lag added is really weak, and that according to the FPS values that I gave you it seems appropriate to activate it, so I say BANCO !!!!!!!!

By the way, my value of pre-rendered frames is equal to 1: is this useful and better to decrease lag input ? Thanks guys.

GTX 780 slightly OC, i5 2500K + 15% OC, PCIe X16 2.0, 16GB RAM 1372Mhz, SSD

 

pre-rendered frames=1 - everyone advises this so I would leave it that way

You could try setting "Render Once Per VSync" to "3" in Player.JSON
It helped with smoothness for me in previous build.

 

None of this applies to VR userss does it ?

 

V-sync won't lessen the load on your eyes. If you have problem with eyes, it would be better to lower the screen luminosity or screen back illumination. This could add lag if you have a TV as a monitor. I do have one (LG), and whatever I do with TV color settings, it adds lag. I think it's because on how the TV manages colors. Look on your TV manual to see what are their recommended settings for PC use. For example, with my LG I had to manually rename the input to PC to enable PC related settings and they suggest the use of "Game Mode".
Another solution for eye problems could be to put a lamp behind the monitor pointed toward the wall, to lower the luminosity difference in your point of view.
On the other hand, synchronization could help with headaches, some people can't stand tearing and "jumpy" videos.

Use Fast Synchronization if you don't like to see a teared video at the cost of some lag (but much less compared to normal synchronization). If you don't mind about tearing, you may run without synchronization and use a framerate limiter to lower GPU usage, and with that temperatures and power draw, or no limit at all if you don't care.
If you only care about lag, the best way it's no synchronization at all.

If you are in the market for a new monitor, this site will help you to choose one with low lag: https://displaylag.com/

It should help by shortening the frame queue, only if you use standard synchronization. But still will be slower than Fast Sync.

In the tests I've made, only with standard synchronization I can get a really fluid video. Enhanced Synchronization (I have an AMD) was almost like no synchronization at all, except for the absence of tearing. Since I don't care about tearing, I go with no synchronization but I limit my framerate to lessen the load on the GPU (which has been successfully brought back from the dead backing it).
I'd like to hear what it is like with Fast Sync.

 

I have no clue... would need VR to know.

 

rF2 sync setting NVidia sync setting Observation
GPU......................Use application setting... No tearing, ~5% loss of fps, microstuttering
Video....................Use application setting... No tearing, locked to vertical sync for fps, visually smooth
None....................Use application setting... Bad tearing, full fps, tearing makes my eyes water when negotiating turns
None.................... Fast................................... No tearing, full fps, smooth as Video (vSync)
Video.................... Fast................................... No tearing, full fps, smooth as Video (vSync) [seems like Fast overrode rF2's vSync]

Test was conducted with content that stayed above the monitor refresh rate (fixed 60 Hz). Triple monitors in multiview, framerate capped at ~80 fps. Panels are IPS, so tearing results in more blur than TN.

I'll try to repeat the test with content below monitor refresh rate.

 

Correct

 

For me 1110 introduced micro stuttering that I did not previously have. Stuttering most noticeable when cornering where there are objects that are being drawn in the background.
My AMD R9 390 using the latest Raedon control panel has always had vertical sync set to always off. Within the vertical sync setting tab ENHANCED Sync as described by DOND33 post #5 above was the answer. Using frame rate control set to a of max 120FPS with adaptive multisampling and use application settings totally removed all of the stuttering with the game running at constant 120FPS 11 cars on starting grid.
All settings in game max except for shadows set at medium and motion blur set to optimal.
AA level 3
PP Low

 

If you dont have a variable refresh rate monitor nor a system that can maintain really high frame rates to make better use of fast sync, you can use Low Lag Vsync.