ULMB+GSYNC "Hack" // How to tell it's working?

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.
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PanzerIV
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ULMB+GSYNC "Hack" // How to tell it's working?

Post by PanzerIV » 28 Mar 2018, 04:29

Hello, I recently acquired a (Acer XB271HU) which is my very first G-Sync monitor. I just tryed the custom resolution and followed all the steps below and I THINK it is working but I have no confirmation as it isn't something officially supported by Nvidia for some dumb reasons. My monitor's OSD says I am in "ULMB" mode and I can confirm on TestUFO. I also had to put the brightness to 100% to help. I'm at 120Hz and I've set BF1 accordingly. I've also enabled in the (Nvidia Control Panel) the "G-Sync Indicator" so it shows a huge button on the left of the screen when it is enabled while I game and it is checked as enabled in the Nvidia Panel, yet I don't think I could usually enable the box while being in ULBM on my monitor's OSD.

Anyhow I can tell for 100% sure that G-Sync is working in-game and that ULMB is working on Test-Ufo if I alt-tab out of my game but how do I tell if both are working together in BF1 at the same time? It would seem quite unlogical for the strobing to be working on TestUfo in the background but not in BF1 in the foreground, and there is no "2 seconds black screen" when I alt-tab out so it's not like if one of these 2 features would toggle on/off while doing so. Does that mean that they are both working together even if I have no confirmation anywhere? My frame rate is usually on average at 100-110FPS as I know it only works between 85-120 even though the monitor can go up to 165Hz, no reason why though.
First, switch to a refresh rate other than 120Hz. Like 144 or 100. Then:
Then run CRU. Find the entry for 2560x1440@120Hz. It's probably in the extension block (the box at the bottom). Double click the extension block entry. Once you find the 2560x1440@120Hz entry, double click it. A dialog will open that looks like this:
www.blurbusters.com/wp-content/ ... astyx.jpeg
Click the "Total" radio box. Then in the second column "Vertical", add 5 to the number you see there. If for example it's 1525, make it 1530. Whatever it is, just add 5.
Click OK on everything until CRU closes.
In the NVidia panel, disable G-Sync. Close the NVidia panel.
In the CRU directory, run "restart.exe".
Open the nvidia panel and select 120Hz.
In the monitor's OSD, enable ULMB.
In the nvidia panel, enable G-Sync.
In the "3D settings" in the nvidia panel, make sure the "preferred refresh rate" setting is "application preference", otherwise games will automatically switch to 144Hz where this hack doesn't work.
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Re: ULMB+GSYNC "Hack" // How to tell it's working?

Post by Chief Blur Buster » 28 Mar 2018, 06:21

Regarding ULMB+GSYNC hack at viewtopic.php?f=4&t=2883

-- You should get erratic flickering now and then. Such as variable-rate flickering during things like disk-asset-loading moments.
-- You'll also see none of the usual "strobed microstutteriness" that you usually get with VSYNC OFF -- instead strafing and automatic horizontal/verticals motions look TestUFO-smooth in-game at any framerate.

...Then it's obvious it's working in game. That said, ULMB+GSYNC combo hack has a very tight usable VRR range (~75Hz-120Hz, ideally capped to ~118fps using RTSS or in-game).
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       To support Blur Busters:
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Sparky
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Re: ULMB+GSYNC "Hack" // How to tell it's working?

Post by Sparky » 28 Mar 2018, 12:17

If you wave a pencil in front of the monitor and it appears as several distinct shadows, ULMB is working. If the pencil is one continuous blur, ULMB is not working.

If your framerate changes and animation stays smooth, g-sync is working.

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Re: ULMB+GSYNC "Hack" // How to tell it's working?

Post by RealNC » 28 Mar 2018, 13:28

Or just set RTSS to 60FPS. If ULMB is active, oh trust me, you'll know, because the flicker will be intolerable.
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PanzerIV
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Re: ULMB+GSYNC "Hack" // How to tell it's working?

Post by PanzerIV » 30 Mar 2018, 01:52

Sparky wrote:If you wave a pencil in front of the monitor and it appears as several distinct shadows, ULMB is working. If the pencil is one continuous blur, ULMB is not working.
Wow what a simple yet very nice trick to see if ULMB is working! Sure I could already guess by the lower brightness but without using a pencil, just using my index quickly would do the trick to see if it was on or off. It is very obvious moving it just beside the monitor or right in front of a strobbed monitor :o It's just harder to tell for G-Sync.
Chief Blur Buster wrote:-- You should get erratic flickering now and then. Such as variable-rate flickering during things like disk-asset-loading moments.
-- You'll also see none of the usual "strobed microstutteriness" that you usually get with VSYNC OFF -- instead strafing and automatic horizontal/verticals motions look TestUFO-smooth in-game at any framerate.

...Then it's obvious it's working in game. That said, ULMB+GSYNC combo hack has a very tight usable VRR range (~75Hz-120Hz, ideally capped to ~118fps using RTSS or in-game).
I've finally got it to "work" in Battlefield 1 and I did expect the erratic flickering during the menus even if I don't understand why it does that, but it's not a big deal anyway and it has been confirmed by everyone so I was okay with that... HOWEVER, even in-game I would get those erratic flickering very often if not even all the damn time when moving around yet I was testing in an empty server and being almost always at 120FPS, never getting any lower than 110FPS so no major spikes and always within the usable VRR range. Do you know what could cause this cause seriously it was horrible and way worse than only using either G-Sync or ULMB! :o

Isn't the (ULMB+G-Sync) hack only working witin 85-120Hz or is it more exactly, 75-120Hz?

If this can help to diagnose my issue, I've done all the steps suggested BUT I haven't used yet RTSS as I've tryed instead to use (Fast V-Sync) through the Nvidia Control Panel, and I've set in BF1's menu (Limit FPS to Refresh Rate) yet I did sometime see my framerate going at 121-122 O_o I don't know if fast v-sync is causing the issue when combined with that trick, if V-Sync needs to be OFF or ON within the Nvidia panel and always to disabled in-game... or if it is because I haven't limited through RTSS my frame rate 0.007FPS below my refresh rate hmm :|
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Re: ULMB+GSYNC "Hack" // How to tell it's working?

Post by Chief Blur Buster » 30 Mar 2018, 13:43

ULMB+GSYNC is not always useful for every single game -- different people are sensitive to the erratic flickering effect of ULMB+GSYNC. This is the dream, but the reality is the variable-rate flicker can be distracting to many people. Some monitors do a slightly better job I would suspect. Some people don't see it as much or don't mind as much, and some games just do it much worse than others.

The problem is the venn diagram of ULMB+GSYNC is much smaller than ULMB-only and GSYNC-only. It's a good tool for some people for select games, but it's hard to figure out which applications it works best with -- it requires extremely consistent and/or slowly-varying frametimes. Yes, you can try using RTSS, and it will smooth out the variable rate flicker at the max framerates -- RTSS is a more stable framerate cap.

Even a 50 microsecond variance in frame time can cause noticeable ULMB flicker, since adding 50ms extra blacktime to a 1ms ULMB strobe flash is a 5% difference in brightness (1000 microseconds divided by 50 microseconds = 5% brightness difference). So microsecond variations in strobe-length-versus-black-length actually create human-visible flicker. That is why ULMB+GSYNC is so difficult to get flicker-free. So that's why you need impeccable framepacing and smooth framerate modulations when it comes to reducing ULMB+GSYNC flicker

In the long term future, it would actually be easier to engineer best-of-both-worlds comfort in a 1000Hz display to combine ULMB+GSYNC without strobing (see http://www.blurbusters.com/1000hz-journey ...) -- we expect this could become a reality by approximately year 2025.

Personally, most people would prefer 100 Hz ULMB + HOWTO: Low Lag VSYNC ON (using FastSync) to get a much better stutter-free ULMB experience. That is, lower your ULMB refresh rate to cover the frame rate dips as much as possible, and then synchronize frame rate to refresh rate for the ideal triple lock (frame rate = refresh rate = strobe rate) for the most perfect possible blurless-stutterless motion without the variable flicker effect.
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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: ULMB+GSYNC "Hack" // How to tell it's working?

Post by masterotaku » 31 Mar 2018, 10:50

PanzerIV wrote: Isn't the (ULMB+G-Sync) hack only working witin 85-120Hz or is it more exactly, 75-120Hz?
No. The hack works in single strobed mode from ~40Hz to your maximum refresh rate (defined by your custom resolution). Under that ~40Hz number it will start to double strobe.

Flickering heavily depends on the game and engine. You should try games known for having perfect pacing. Things like Dark Souls 1-2-3, emulators, these Devil May Cry games I'm just playing, etc.

I'm fine with low refresh rates in this mode, even when I'm in the 40-60fps range, because it's so smooth and perfect (low motion blur, no double image, no input lag, no tearing).

Try not to reach your max refresh rate in fps. Hitting the vsync limit can create more flickering when it reaches that limit and then not.

Remember: it's an unofficial hack, and making it comfortable for everyone in the future in an official way will be very hard, in the ways Chief has explained already (variable strobe length to avoid variable brightness, lower limits for strobing, etc).
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Re: ULMB+GSYNC "Hack" // How to tell it's working?

Post by Chief Blur Buster » 31 Mar 2018, 13:19

masterotaku wrote:No. The hack works in single strobed mode from ~40Hz to your maximum refresh rate (defined by your custom resolution). Under that ~40Hz number it will start to double strobe.
Yes, it strobes as low as 40 Hz -- I only simply mentioned 75 Hz as the lower limit for a typical comfort factor.

That said, you're right -- if you can tolerate such flicker, it does strobe pretty well much lower than 75 Hz.
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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