Blur Buster's G-SYNC 101 Series Discussion

Talk about NVIDIA G-SYNC, a variable refresh rate (VRR) technology. G-SYNC eliminates stutters, tearing, and reduces input lag. List of G-SYNC Monitors.
monitor_butt
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Re: Blur Buster's G-SYNC 101 Series Discussion

Post by monitor_butt » 20 Jun 2017, 11:50

jorimt wrote:
RealNC wrote: Lower frametimes are causing V-SYNC OFF to deliver more updates to the screen per scanout, so in some instances (depending on the V-SYNC OFF refresh rate/framerate ratio), mouse response could theoretically appear to be a little more responsive, as updates are reaching the screen more frequently than at 144Hz.
So I wouldn't need a 400hz screen to see the benefit or a lower ms/f latency when it exceeds my refresh rate as previously mentioned?

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kurtextrem
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Re: Blur Buster's G-SYNC 101 Series Discussion

Post by kurtextrem » 20 Jun 2017, 11:52

I don't think csgo pros are playing with gsync when they're able to get 800? fps or so.
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Glide
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Re: Blur Buster's G-SYNC 101 Series Discussion

Post by Glide » 20 Jun 2017, 11:53

jorimt wrote:I was using out-the-box-settings sans "Game Mode." I will clarify that in the article. To be clear, I never had Game Mode, Game DVR, or fullscreen optimizations enabled for the test games during actual tests in the article.
So you specifically disabled the fullscreen optimizations then?
They're enabled by default, and not a part of Game Mode.
They're a compatibility option for the game's executable.
jorimt wrote:As I stated in the borderless/windowed test section of my article (which I'm not ready to "call" yet, until further testing/corroboration; there could be more factors than I accounted for), no combination of any setting could get the screen to tear in either mode. So I don't think it's quite as simple as Game Mode turning borderless/windowed into the DX12 version, otherwise I would have seen, one, tearing, and two, no added 1 frame of delay from the DWM with the non-G-SYNC scenarios in my tests.
That's very strange. I've tried about 20 games off that list, and just tested a few games again, confirming that they behave as expected:
Fullscreen Optimizations Enabled = Tearing in Borderless Windowed Mode with V-Sync/G-Sync disabled.
Fullscreen Optimizations Disabled = No tearing in BWM with V-Sync/G-Sync disabled.

FSE Mode also seems to switch much quicker when you alt-tab with the optimizations enabled too.
Fullscreen Optimizations are not linked to the Game Mode setting in any way.

The only thing I can think of, is that I believe it switches back to the old BWM if something is overlaying the game window - though I haven't tested it.
Not an injected overlay like RTSS/Afterburner stats, but another desktop window.
jorimt wrote:Bottm-line, borderless/windowed G-SYNC did not add 1 frame of delay, non-G-SYNC did (Game Mode on or off).
Well that's good to hear, regardless.

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jorimt
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Re: Blur Buster's G-SYNC 101 Series Discussion

Post by jorimt » 20 Jun 2017, 12:05

monitor_butt wrote: So I wouldn't need a 400hz screen to see the benefit or a lower ms/f latency when it exceeds my refresh rate as previously mentioned?
As stated here before, if you couldn't care less about tearing or microstutter, then just stick with V-SYNC OFF and super high framerates. This will ensure the lowest possible lag, but it will never be delivering a single frame in sync with the display's scanout.

And, no, even with V-SYNC OFF and high framerates, you're 144Hz display is still limited by its 6.9ms scanout speed. At 400Hz, the scanout speed would actually be much higher, which means frame delivery would be as well. At this speed, V-SYNC OFF would be delivering no more than two updates per scanout at 400 FPS to the display at 400Hz, which means both G-SYNC and V-SYNC OFF would have roughly the same delivery speed.

Everything is limited by the scanout.
Glide wrote:So you specifically disabled the fullscreen optimizations then?
I did. It was a new setting with unknown effect, and I needed a proper control, so safer than sorry.
Glide wrote:That's very strange. I've tried about 20 games off that list, and just tested a few games again, confirming that they behave as expected:
Fullscreen Optimizations Enabled = Tearing in Borderless Windowed Mode with V-Sync/G-Sync disabled.
Fullscreen Optimizations Disabled = No tearing in BWM with V-Sync/G-Sync disabled.
Another reason I stated very clearly I'm not ready to call the results; they seem dependent on the give configuration. I only tested that scenario on user request; I didn't plan on including it originally.

I'm glad I did include it, but I could not replicate that behavior. It would be interesting to know more details about your system specs, driver versions, OS version and settings though.
(jorimt: /jor-uhm-tee/)
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Glide
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Re: Blur Buster's G-SYNC 101 Series Discussion

Post by Glide » 20 Jun 2017, 12:14

jorimt wrote:I'm glad I did include it, but I could not replicate that behavior. It would be interesting to know more details about your system specs, driver versions, OS version and settings though.
Not sure there's much to tell. Ryzen 1700X paired with a GTX 1070, display is a PG348Q.
It was a clean install of the Win10 CU, and everything is up to date. Windows, NVIDIA drivers (382.53) etc.
Not running a preview build of the OS, just the standard Win10 Pro.

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Re: Blur Buster's G-SYNC 101 Series Discussion

Post by Chief Blur Buster » 20 Jun 2017, 12:18

kurtextrem wrote:I don't think csgo pros are playing with gsync when they're able to get 800? fps or so.
Correct, many eSports pros like VSYNC OFF because massive framerates can bypass scanout lag. This image is useful to understand why competitive and eSports players love VSYNC OFF -- at ultra high frame rates, scanout lag becomes noticeably bypassed!

This illustrative example, at 432 frames per second at 144 Hz, VSYNC OFF -- creates three frame-slices per refresh cycle -- multiple tear lines per refresh cycle.

Image

We have invented the "Filmreel" metaphor based on high speed video analysis. I have analyzed lots of high speed videos (4 frames rapidly alternating in a cycle), and have observed how display monitor scanout interacts with lag.

One of our most popular high speed videos, is our old high speed video of LightBoost. In non-LightBoost mode, the gaming monitor LCD display clearly scans from top to bottom. Bottom edge always has more input lag! But "VSYNC OFF" actually "cheats" this by interrupting the current scanout with a new frame. We have newer high speed videos (which we will release soon) that clearly illustrate why we invented a filmreel metaphor of explaining scanout latency.

CRT/LCD/OLED: Capable of synchronous scanout directly from the cable, top-to-bottom wipe.
Plasma/DLP: Require scan-conversion (to a non-sequential scan method, such as globally-flashed temoporally dithered subfields).

On displays that synchronously scan from the cable (cable scanout = same speed as panel scanout)....

....When you have 1000fps VSYNC OFF (1 frame = 1 ms), each frameslice adds only 1ms lag relative to the GPU output. As the display scans out seqeuentially, it can continue to display the next frame (with tearing in between). Obviously, many subtle lag factors apply (mouse, cable differences, LCD GtG, etc), but scanout lag is definitely part of the input lag equation, including bottom edge of previous refresh cycle.

Lag can dramatically go down when even the bottom of the screen has only 1ms input lag -- which is faster than the sequential 1/144sec scanout of a 144Hz display. VSYNC OFF can "beat" scanout latency by interrupting the current finite-speed scanout with a new (fresher) frame to hit your eyeballs sooner.

CS:GO and Quake, both still popular today, both achieve 1000fps in VSYNC OFF on current graphics cards.

Once you "spray massive framerates" -- an overkill VSYNC OFF framerate (e.g. 1000fps) -- onto the video cable and onto the display, it noticeably has less lag than GSYNC or FreeSync since it crams a lot of tiny low-lag tearslices to the same refresh cycle that "beats" the scanout latency consistently, every refresh cycle.

1/144sec refresh cycle is 6.9ms scanout lag for bottom edge, mandatory, because of finite speed of display scanout.
1000fps VSYNC OFF can reduce this to 1ms lag by continually interrupting the scanout with fresh frameslices (1000fps = 1ms per frame slice).

That few extra milliseconds savings (+1ms "frame-to-scanout" lag instead of +6.9ms "frame-to-scanout" lag), that extra ~5ms "best-case" competitive advantage (relative to 142fps frame-capped 144Hz GSYNC or FreeSync) can cause you to win the frag in simultaneous-draw situations (equal human reaction time scenarios, shoot-eachother-at-same-time). Screen centre is half that, but some competitive players are primed to react by peripheral vision to bottom edge first (e.g. close-quarter combat or explosion flashes).

This may not matter in novice competitive gaming, but can matter in the elite paid eSports leagues when the bottom edge has almost a full refresh cycle less lag during "overkill framerate VSYNC OFF" situations. This is why you hear many eSports players say they don't use GSYNC.

The higher the max refresh rate (e.g. 240Hz), the faster the scanout is. VSYNC OFF will probably become slightly less important once framerates consistently stay below monitor's maximum refresh rate.

So we need 1000Hz monitors to allow GSYNC or FreeSync to fluctuate nicely between 200fps and 999fps in games like CS:GO and Quake. As we approach this, VSYNC OFF may be able to gradually become unnecessary even in eSports. Then -- simultaneously -- we'd have virtually no lag AND no tearing AND no microstutter. And blur-free "1ms persistence" at high frame rates without adding lag of strobing.

eSports holy grail?

It's going to take a long time before that happens, but anytime framerates go beyond refresh rate, there's still the potential to have quite noticeably less input lag during VSYNC OFF (scanouts that can be interrupted, with a new fresher frame, on the fly, in real time).
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lexlazootin
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Re: Blur Buster's G-SYNC 101 Series Discussion

Post by lexlazootin » 20 Jun 2017, 13:36

@jorimt

The monitor/g-sync chip i have has a very strange set of rules, It's pretty much trying to stay within the rules and trying to figure out what the rules are.

For example at Vertical Total 1098 it would go into 144hz mode, that would mean that you have to keep the Pixel Clock between 320 and 330. You are allowed to raise the VT by 2 or 5 and the Horizontal Total would be completely unlocked.

So to overclock the monitor you would simply lower the HT by a enough so that you can raise the HZ but staying between the Pixel Clock 320 and 330.

You can adjust the Front and Sync but they don't seam to do anything besides the Vertical ones, if you change them from 3 and 5 (respectively) G-Sync would not lock on (Or something) and you would get tearing. If for any reason your HT got below 1200 you would get a tearline in the middle of your screen with a good few frames of input lag between them.

A lot of little weird stuff like that, but for some reason at <1024x768 the rules go crazy again and allow for extreme overclocking.

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Re: Blur Buster's G-SYNC 101 Series Discussion

Post by Chief Blur Buster » 20 Jun 2017, 13:58

It would be interesting if any 240Hz monitor can overclock to 250Hz for 250fps Quake Live gaming.

And perhaps framerates locked to mouse poll rate? (poll-render-deliver 250Hz GSYNC cycle).

And no input-lag yo-yo/sawtoothing effect from minor drift between imperfectly matched refresh rate & frame rates.
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       To support Blur Busters:
       • Official List of Best Gaming Monitors
       • List of G-SYNC Monitors
       • List of FreeSync Monitors
       • List of Ultrawide Monitors

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Re: Blur Buster's G-SYNC 101 Series Discussion

Post by Chief Blur Buster » 20 Jun 2017, 14:34

BTW, some reader posted Jorim's article on Reddit in /r/pcgaming

https://www.reddit.com/r/pcgaming/comme ... _settings/
Head of Blur Busters - BlurBusters.com | TestUFO.com | Follow @BlurBusters on Twitter

       To support Blur Busters:
       • Official List of Best Gaming Monitors
       • List of G-SYNC Monitors
       • List of FreeSync Monitors
       • List of Ultrawide Monitors

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Re: Blur Buster's G-SYNC 101 Series Discussion

Post by RealNC » 20 Jun 2017, 14:42

Yeah, saw it a few hours ago. Might explain why the site appears to be getting hammered :P
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