G-Sync Input lag Review

[Skurge]

Or rather lack of input. Lag is the same as running the game without v-sync. Not less leg as nVidia were saying, but I guess it would be less lag versus V-sync.

Still though. Apart from the price and selection of Monitors. It looks like there really isn't a reason not to get G-sync.

http://www.blurbusters.com/gsync/preview2/

 

[Silverforce11]

Actually, in that review they had more input lag for faster higher fps shooters like CSO on GSYNC.

Looks like if FPS get above 120 it start to have input lag issues. Which is fine since most newer games dont really run all that fast for most gamers.

 

[BrightCandle]

It is an interesting problem that as they approach the refresh rate of the monitor they are having to stall the GPU to wait for the next monitor available slot rather than the GPU waiting on the monitor. It looked like the cross over point was around 120fps, so for minimal input latency you likely don't want to go higher than that.

The big difference between vsync and gsync is that the entire screen is at that latency, whereas with vsync off some of it is at least 16ms older which only increases the perceived latency and also the stutter effect. With gsync the entire screen is the same age and that should mean that the average latency is lower.

 

[pandemonium]

Largely positive results, unless you're beyond 120FPS.

Alternatively, this will push for a higher demand of in-game support with native FPS capping options. A big win in and of itself for the fact that those without G-sync will benefit by not having to run V-sync and allow the graphics engine cap the FPS natively.

Game Developer Recommendations

It is highly recommended that Game Options include a fully adjustable frame-rate capping capability, with the ability to turn it on/off. The gold standard is the fps_max setting found in the Source Engine, which throttles a game’s frame rate to a specific maximum.

These frame rate limiters hugely benefit G-SYNC because the game now controls the timing of monitor refreshes during G-SYNC. By allowing users to configure a frame rate cap somewhat below G-SYNC’s maximum refresh rate, the monitor can begin scanning the refresh immediately after rendering, with no waiting for blanking interval.

One issue is the lack of capability with Lightboost or UltraLightboost.

Also, the limited-time kit is $200 from Nvidia. It also doesn't support audio via the cabling (I doubt a large issue since most gamers don't use their monitor's speakers, but an important note).

 

[bunnyfubbles]

completely positive results considering I would be using ULMB for games where I can maintain over 120fps anyway, although I'm still hoping they find a way to combine G-Sync and ULMB

 

[Anarchist420]

i thought it was direct drive and thus got rid of all display processing lag but i guess i was wrong.

it's an excellent tech though (counters the display makers' stubborn refusal to make IPS displays that can receive 120hz+ signals when they easily could've done so by using DP1.2 instead of low bandwidth DVI/HDMI) and i imagine there could be direct drive monitors with gsync down the road.

 

[Pandamonia]

Personally 59fps cap and Vsync works just great. Im not sure id want to go TN and buy a silly priced monitor when i got the Asus 1440p PLS for half the price nearly.

 

[bystander36]

Actually, in that review they had more input lag for faster higher fps shooters like CSO on GSYNC.

Looks like if FPS get above 120 it start to have input lag issues. Which is fine since most newer games dont really run all that fast for most gamers.

The problem is DX and triple buffering. If you reach your refresh rate and capable of beating it with your FPS, triple buffering will allow the system to start rendering ahead one frame. DX also has a requirement that all frames created be displayed. In this case, you monitor will be displaying 1 frame behind the most current one. With G-sync, it becomes a V-sync system once you reach your refresh cap.

Setting a FPS limit at your refresh rate, or 1 below, fixes the problem as it prevents triple buffering from backing up. You can see how it fixes it in the last couple runs of CS.

 

[bystander36]

i thought it was direct drive and thus got rid of all display processing lag but i guess i was wrong.

it's an excellent tech though (counters the display makers' stubborn refusal to make IPS displays that can receive 120hz+ signals when they easily could've done so by using DP1.2 instead of low bandwidth DVI/HDMI) and i imagine there could be direct drive monitors with gsync down the road.

The reason they do not do this, is most likely due to response times. Actually, this is what I was reading from Asus, when talking about these G-sync monitors.

Having slow response times means that at high refresh rates, pixels are in constant shift. They never reach their color before they are changing again. I guess a lot of people don't care for the ghosting, but they do.

 

[mindbomb]

Personally 59fps cap and Vsync works just great. Im not sure id want to go TN and buy a silly priced monitor when i got the Asus 1440p PLS for half the price nearly.

In my experience, doing the fps cap under refresh rate + vsync thing just ends up disabling vsync. So you immediately notice the lack of input lag, but then you are also susceptible to tearing.

I'm gonna chalk the whole CS:GO thing up to a bug. Gsync should be good for low lag up to 144 fps, given how it is packaged with 144 hz monitors.

 

[bystander36]

In my experience, doing the fps cap under refresh rate + vsync thing just ends up disabling vsync. So you immediately notice the lack of input lag, but then you are also susceptible to tearing.

I'm gonna chalk the whole CS:GO thing up to a bug. Gsync should be good for low lag up to 144 fps, given how it is packaged with 144 hz monitors.

Look at the last 2 runs when they set a FPS limit to 120. The input lag was gone. The problem is definitely switching to V-sync once you go past the displays refresh rate.

 

[mindbomb]

the refresh rate was 144hz

 

[Mark Rejhon]

Largely positive results, unless you're beyond 120FPS.

Actually, the GSYNC cap-out trigger point for CS:GO seems to be somewhere closer to 140fps. I wasn't able to have enough time to test other values before publishing the review.

Ideally, fps_max 143 shouldn't have triggered this behavior, but it may be a CS:GO specific quirk. But the good news is that in-game frame-capping (not driver frame-capping) works pretty well, to prevent slamming against the GSYNC rate limit (and causing latency).

 

[bystander36]

the refresh rate was 144hz

Yes it was, but he had to hold back the FPS below that rate to prevent the V-sync+triple buffering like latency. 143 wasn't enough, but 120 was, and Mark just mentioned that 140 works as well.

We can assume the FPS were going beyond 140.

 

[blastingcap]

Is this a hardware limitation or software?

 

[BallaTheFeared]

Or engine?

 

[bystander36]

Is this a hardware limitation or software?

We already know that G-sync only operates between 30 FPS up to the max refresh rate of 144hz, although due to G-sync's polling, it may get limited at about 140 FPS. Once you reach the outer bounds of G-sync, it probably behaves like V-sync. With DX and triple buffering, when you hit your refresh rate, latency kicks in due to DX rules.

 

[amenx]

First hand users experience of Nvidias GSync kit, installation and impressions.

http://forums.guru3d.com/showpost.php?p=4745546&postcount=35

 

[bystander36]

First hand users experience of Nvidias GSync kit, installation and impressions.

http://forums.guru3d.com/showpost.php?p=4745546&postcount=35

Besides the user experience part, which seems on par with other reviews, I noticed he mentioned the Lightboost mode, which now includes 85/100/120hz modes. 85hz will give you the chance to use Lightboost in more circumstances, though I don't know if I'd want to once you get used to G-sync.

 

[Midwayman]

Besides the user experience part, which seems on par with other reviews, I noticed he mentioned the Lightboost mode, which now includes 85/100/120hz modes. 85hz will give you the chance to use Lightboost in more circumstances, though I don't know if I'd want to once you get used to G-sync.

Supposedly the new benq monitors coming out this spring (xl2720z, xl2420z) will support strobing from 75hz to 144hz in 1 hz increments. They aren't gsynch, but it looks like strobing might start working for folks without uber GPUs.

 

[bystander36]

Supposedly the new benq monitors coming out this spring (xl2720z, xl2420z) will support strobing from 75hz to 144hz in 1 hz increments. They aren't gsynch, but it looks like strobing might start working for folks without uber GPUs.

If they can do that, maybe there is hope for G-sync with strobing in the future.

 

[VulgarDisplay]

I know on my Asus monitor strobing makes everything completely washed out. I can't tell the difference with it off vs. On in terms of clarity.

 

[DigDog]

i'd be ok with "up to" 8ms input lag.

 

[bystander36]

I know on my Asus monitor strobing makes everything completely washed out. I can't tell the difference with it off vs. On in terms of clarity.

According to the technical spec's, and the above review, the new G-sync strobing does not wash out the colors anymore. They incorporated new tech to counteract color shifting due to refresh rates and strobing.

Check this post out. It was quite informative: http://forums.anandtech.com/showpost.php?p=35954614&postcount=490

 

[Anarchist420]

i'd be ok with "up to" 8ms input lag.

+1. no more than 10 ms from the monitor (processing, pixel response, and sync method) and gamepad combined is very technically possible and reasonable if one had a really good IPS (or TN, but TN panels suck and i dont understand why they are still made) panel with gsync and DDM or processing that didnt add much lag and with <= 2ms (effective) gamepads.