Gsync & 144Hz monitors

[Jonathan Cave]

Does tearing occur when you are rendering less frames than the fixed refresh rate of the monitor ?

e.g. 80fps on a 144hz non gsync monitor...

Also Gsync combined with vsync on will always ensure you are using Gsync, with gsync on and vsync off, allows you to dip in and our of gsync - so what circumstances would you want gsync with vsync off?

 

[J_E_D_70]

Yes, tearing occurs when the refresh and fps are out of sync regardless of which is higher.

High refresh masks the issue for most folks as the tear is visible for a shorter amount of time compared to 60hz.

You don't turn vsync on with gsync. Gsync just does its thing. You would use fast sync if you had fps much higher than the refresh rate.

With witcher 3 i ran gsync since fps at 1440p ultra were 50-60. I don't use it on bf1 since I get 90+ fps at 1080p and things are happening so fast I can't notice any tearing that's occuring.

 

[cilliers]

Q: Does tearing occur when you are rendering less frames than the fixed refresh rate of the monitor ?
A: Yes and also when framerate exceeds panel refresh rate.

Q: what circumstances would you want gsync with vsync off?
A: Never. You would typically use Gsync with Vsync as a first option. If you have low-ish framerates then you can also try the "fast" option under vsync, but it will not be as smooth. At least the tearing will be gone.

I found this video super duper useful: https://www.youtube.com/watch?v=L07t_mY2LEU

 

[J_E_D_70]

Nope - you do NOT turn vsync on with gsync. Gsync replaces vsync - read here:
http://www.geforce.com/hardware/technology/g-sync/faq

And

http://www.nvidia.com/coolstuff/demos#!/g-sync

 

[cilliers]

Nope - you do NOT turn vsync on with gsync. Gsync replaces vsync - read here:
http://www.geforce.com/hardware/technology/g-sync/faq

And

http://www.nvidia.com/coolstuff/demos#!/g-sync

 

[iamacow]

Nope JED70 is right. I have a 165hz Gsync monitor that I am using right now. I turn off Vsync in games because it overrides GSync allowing the game engine to set the frame rate not the monitor.

So an example, Borderlands (any of them). If I left VSYNC on, it would match whatever settings I have in game, not the 165hz refresh rate of the monitor. If I leave both on, I get latency issues like you normally do with VSYNC, with it off, It runs like normal and my monitor is matching the FPS (since it has its own built in counter).

 

[J_E_D_70]

Guess there is a twist - if you have a game that renders higher than the monitor refresh you *can* turn vsync on in the control panel (not the game) to prevent tearing as gsync turns itself off above the refresh of the monitor. If your fps never go above the refresh then vsync on/off in the control panel doesn't really change anything.

Vsync should always be off in game.

 

[Jonathan Cave]

Thanks for all contributions so far,

Gsync ON & Vsync ON (NVCP) = always using gsync as the driver forces the fps to not exceed monitor refresh rate and therefore gsync, syncs your GPU frame to the monitor frame.
Gsync ON & Vsync OFF (NVCP) = Gsync on when rendering </ max monior refresh rate and gsync OFF when fps > monitor refresh rate

In games like cs:go i don't notice any difference @ 300fps (no sync) vs 144fps (gsync) and to save gpu rendering 156 un-used frames i enable vsync.

I think i've answered my own question : http://www.geforce.com/whats-new/articles/g-sync-gets-even-better

For enthusiasts, we’ve included a new advanced control option that enables G-SYNC to be disabled when the frame rate of a game exceeds the maximum refresh rate of the G-SYNC monitor. For instance, if your frame rate can reach 250 on a 144Hz monitor, the new option will disable G-SYNC once you exceed 144 frames per second. Doing so will disable G-SYNCs goodness and reintroduce tearing, which G-SYNC eliminates, but it will improve input latency ever so slightly in games that require lighting fast reactions.

To use this new mode, set “Vertical sync” to “Off” on a global or per-game basis in the “Manage 3D settings” section of the NVIDIA Control Panel. When your frame rate exceeds your monitor’s rated G-SYNC refresh rate, for example 144Hz, G-SYNC will be disabled.

For games like cs:go you 'ever so slightly' reduce input lag that gsync has by having vsync off i.e. running 300 fps + tearing.

 

[iamacow]

Vsync introduces input lag no matter how you word it. Gysnc does not, though it does not work below 30fps. Vsync waits for the monitor to be ready for the next frame.

Since frame-rate goes up and down, you get random bits of input lag when it waits for the next available frame slot. higher refresh rate helps this but won't solve the underlying problem. If your video card does not line up when rendering frames (which it cannot), than it will show input lag since its waiting for the next frame. Say you have 60 frames per second (1000ms). Divided that by 60 you get 16.6ms per frame. If the next frame comes in anytime after 16.6ms than it will hold the last frame until the rest of the time on the second frame. This could be 5ms all the way to 16.5ms. THIS IS WHERE INPUT LAG COMES FROM ON VSYNC!!!!

Gsync has a add-on card in the monitor with frame buffer and software to time the frames to match. So say the game is running at 45FPS, it will change the monitor to 45hz to allow the frames to stay in sync and remove screen tearing and input lag. The monitor does not wait on any frames, it simply matches what is being outputted.

So in short, having Vsync on and GSync defeats the purpose of GSync. You are wasting money and have no reason to even have a Gsync monitor. I'll take it off your hands

 

[Jonathan Cave]

Vsync introduces input lag no matter how you word it. Gysnc does not, though it does not work below 30fps. Vsync waits for the monitor to be ready for the next frame.

Since frame-rate goes up and down, you get random bits of input lag when it waits for the next available frame slot. higher refresh rate helps this but won't solve the underlying problem. If your video card does not line up when rendering frames (which it cannot), than it will show input lag since its waiting for the next frame. Say you have 60 frames per second (1000ms). Divided that by 60 you get 16.6ms per frame. If the next frame comes in anytime after 16.6ms than it will hold the last frame until the rest of the time on the second frame. This could be 5ms all the way to 16.5ms. THIS IS WHERE INPUT LAG COMES FROM ON VSYNC!!!!

Gsync has a add-on card in the monitor with frame buffer and software to time the frames to match. So say the game is running at 45FPS, it will change the monitor to 45hz to allow the frames to stay in sync and remove screen tearing and input lag. The monitor does not wait on any frames, it simply matches what is being outputted.

So in short, having Vsync on and GSync defeats the purpose of GSync. You are wasting money and have no reason to even have a Gsync monitor. I'll take it off your hands

Nvidia designed (and released) gsync to be used WITH vsync. They only allowed gsync with vsync off at a later date to reduce input lag when rendering > monitor refresh rate.

 

[JayBeeAB]

This might shed some additional insight: http://forums.blurbusters.com/viewtopic.php?f=5&t=3073

Namely

"On release, G-Sync’s ability to fall back on fixed refresh rate v-sync behavior when exceeding the maximum refresh rate of the display was built-in and non-optional. A 2015 driver update later exposed the option.

This update led to recurring confusion, creating a misconception that G-Sync and v-sync are entirely separate options. However, the "Vertical sync" option in the control panel actually dictates whether, one, the G-Sync module compensates for frametime variances (see "Upper Frametime Variances" in "G-Sync Range" section), and two, whether G-Sync falls back on fixed refresh rate v-sync behavior; if v-sync is "On," G-Sync will revert to v-sync behavior above its range, if v-sync is "Off," G-Sync will disable above its range. Within its supported range, G-Sync is the only synchronization method active, no matter the v-sync setting."

 

[Jonathan Cave]

This might shed some additional insight: http://forums.blurbusters.com/viewtopic.php?f=5&t=3073

Namely

"On release, G-Sync’s ability to fall back on fixed refresh rate v-sync behavior when exceeding the maximum refresh rate of the display was built-in and non-optional. A 2015 driver update later exposed the option.

This update led to recurring confusion, creating a misconception that G-Sync and v-sync are entirely separate options. However, the "Vertical sync" option in the control panel actually dictates whether, one, the G-Sync module compensates for frametime variances (see "Upper Frametime Variances" in "G-Sync Range" section), and two, whether G-Sync falls back on fixed refresh rate v-sync behavior; if v-sync is "On," G-Sync will revert to v-sync behavior above its range, if v-sync is "Off," G-Sync will disable above its range. Within its supported range, G-Sync is the only synchronization method active, no matter the v-sync setting."

so if vsync = on and gsync = on, you always have gsync enabled as you can't exeed monitor refresh rate?

 

[JayBeeAB]

so if vsync = on and gsync = on, you always have gsync enabled as you can't exeed monitor refresh rate?

To be honest its not very clear. My understanding is that you can leave V-Sync off if you set your frame limiter to approx 10fps below your monitors max refresh rate then you won't get tearing. If you enable V-Sync you can set the fps to 1-2 below max refresh rate and all will be good. The article refers to this as "Upper Frametime Variances". If you don't, you'll get tearing on the lower part of the screen as the fps approaches the max refresh rate of the monitor. But if you're still within the "G-Sync range" its still G-Sync in control so you shouldn't get stutter thats synonymous with traditional V-Sync.

I think if you don't set the limiter then with V-Sync off you'll get tearing as you move out of the G-Sync range. If you set it on you'll get 1-3 frames of delay, but no tearing.

So to summarise, the best option for 99% of people appears to be

V-Sync On (some people say only use the control panel, not the in-game V-Sync).
G-Sync On
Frame Limiter 2fps below monitor refresh rate.

This configuration should get you optimal results with no tearing, no stutter and no latency (beyond monitor input lag).

 

[J_E_D_70]

Cheers to everyone for all the info! It was clear as mud now a bit better for all I think. Agree, but everything I've read says gsync off in game. Makes sense to have it on in the control panel since nvidia should play nice with itself.

I'm still running with it off as I haven found a game that runs at 144fps yet due to the settings I use.

Love learning new info!

 

[iamacow]

Whaa?? Why own a Gsync monitor is you are going to leave it OFF? I leave it ON in the control panel always and that is how it should be.

 

[J_E_D_70]

I meant vsync off. Gsync stays on.

 

[UnspokenWhale]

In games like cs:go i don't notice any difference @ 300fps (no sync) vs 144fps (gsync) and to save gpu rendering 156 un-used frames i enable vsync..

In that situation Fast Sync is probably the best option.