Top of screen always fluctuating when using scanlinesync

[mist]

Monitor 60hz. Game - Quake Champions(2017) Videocard - rx580 I set tearline at bottom of screen, but i see picture fluctuating width 3-5cm at top of screen. Why its happening? Fluctuating is decreased when i lift up tearline at 5cm from bottom edge of screen, but its uncomfortable for eyes Fps without synchronization never drops under 90-100fps, but fps is very variable from 90 to 140.

[Framerate]
Limit=60
SyncFlush=1
SyncHotkeys=1
SyncScanline0=-65
SyncScanline1=0
SyncTimeout=1
LimitDenominator=1
LimitTime=0
SyncPeriods=0

[Chief Blur Buster]

Monitor 60hz. Game - Quake Champions(2017) Videocard - rx580 I set tearline at bottom of screen, but i see picture fluctuating width 3-5cm at top of screen. Why its happening? Fluctuating is decreased when i lift up tearline at 5cm from bottom edge of screen, but its uncomfortable for eyes Fps without synchronization never drops under 90-100fps, but fps is very variable from 90 to 140.

[Framerate]
Limit=60
SyncFlush=1
SyncHotkeys=1
SyncScanline0=-65
SyncScanline1=0
SyncTimeout=1
LimitDenominator=1
LimitTime=0
SyncPeriods=0

[/quote]

That's because there's a time differential between the targeted scan line number and the actual tearline location. Sometimes it's only a few pixels off, but other times it varies quite a lot because of many factors (driver overheads, power management, GPU processing, CPU processing). Slower GPUs will have more problems.

You can reduce volatility by:
(A) Try SyncFlush=2 (might not work anymore, but it will hog GPU power)
(B) Disabling power management on both GPU and GPU
(C) Custom Resolution Utility with Large Vertical Totals (bigger VBI = bigger jitter margin to hide tearline between refresh cycles), see information in Quick Frame Transport about this. If your 60Hz panel's memory buffer is capable of accepting a signal at a higher velocity, this could reduce input lag too (hitting two birds with one stone!)

Imagine refresh cycles as an endless loop. Pixels are delivered from computer to monitor one pixel row at a time, top to bottom (high speed videos at www.blurbusters.com/scanout ). So a delay moves a tearline downwards. And the bottom edge of screen wraps around to the top edge of the next refresh cycle. The VBI is often small, so any bottom-edge can jitter wraparound back to top-edge. Make the VBI bigger, and it's easier to hide a jittering tearline between refresh cycles.



If the tearline vibrates a lot, the vibration amplitude probably exceeds the vertical thickness of the VBI (it's kind of like offscreen vertical resolution that separate consecutive adjacent refresh cycles). Making the VBI bigger via a Custom Resolution Utility (Large Vertical Totals) may help hide the VSYNC OFF tearline jitter offscreen better.

This may be harder on some 60Hz panels, but some panels can accept a signal far faster than their actual refresh rates (e.g. 60Hz panel accepting a "60Hz" refresh cycle in 1/80sec or 1/120sec as an example) creating bigger VBI pauses between refresh cycles, convenient for (A) lowering input lag of synchronized framerate, and (B) hiding tearline between refresh cycles better

[mist]

Thanks for explanation! Its bit hard to understand for me.

(B) Disabling power management on both GPU and GPU

How Disabling power management can help me? Where i can do that(from bios, drivers or control panel > power mangement)?

Custom Resolution Utility with Large Vertical Totals

Use that can be dangerous for monitor or videocard?

what value i can set here?

[Chief Blur Buster]

Thanks for explanation! Its bit hard to understand for me.

(B) Disabling power management on both GPU and GPU

How Disabling power management can help me? Where i can do that(from bios, drivers or control panel > power mangement)?

Use that can be dangerous for monitor or videocard?

Generally, no, it isn't.

what value i can set here?

I can't guide on exact number there -- it varies hugely depending on the monitor -- but I can inform on the technique.

First, if you've never used a Custom Resolution Utility, learn how the numbers are geometrically mapped into an overscanned signal (see diagram). The easiest way to visualize the numbers in the Custom Resolution Utility is that they're hidden pixels beyond edges of the screen, like this:



They're simply signal formatting / overscan / synchronization markers), in accordance to this diagram. VBI is the total sum of (Vertical Back Porch + Vertical Sync + Vertical Back Porch), basically VBI is anything verticals that is not visible. And Vertical Total is vertical resolution plus the size of VBI.

Put the radio button on the "Total" row, and adjust Total that way. The other numbers will be automatically calculated. You will have to repeatedly test until it works.

The main number you will probably want to increase is the Vertical Total. Increase it in small amounts. You can also kind of binary-search your way towards an ideal setting. (e.g. VT1125 -> VT2250 -> VT1500 -> VT1600 -> VT1550) if you understand what a "binary search algorithm" means -- basically hone your way quickly to a setting that doesn't black out the screen, since large VTs will just create an OUT OF SYNC message which takese 15 seconds to go away when Windows automatically comes back. (Don't touch keyboard or mouse). But the rule of thumb is the bigger the VT, the bigger the VBI is. You can ignore the other numbers, and just change the Vertical Total only. ("Total" row under "Vertical" column)

The problem is when the screen blanks out, you have difficulty going back to the original setting. So it's easier to experiment with a 2-monitor setup, with the primary monitor temporarily set to a different monitor than the one you're tweaking. Or obtain a copy of software that alloows you to switch resolutions via a hotkey (e.g. DisplayFusion) so that you can revert safely quickly without needing to reboot into Safe Mode.

Currently, it is quite frustrating doing this type of tweaking, it's harder on AMD than on NVIDIA, because AMD Catalyst Control Center doesn't provide these means of testing Vertical Totals in a "real-time manner" the same way NVIDIA Control Panel is able to.

Here's a helpful data point: Some of these Samsung 1920x1200 monitors are overclockable to about 72Hz-75Hz, but if you're concerned about eliminating tearlines, it's better to use the bandwidth towards quicker delivery of 60Hz refresh cycles (e.g. 60Hz refresh cycle transmitted in 1/72nd or 1/75th second, via a Vertical Total that's about 72/60ths or 75/60ths bigger than vertical resolution), creating a bigger VBI for hiding tearlines in (via RTSS Scanline Sync). Try 72/60ths initially (Vertical Total 1440), for something that is lower risk of black out, but no guarantee -- be prepared to reboot to Safe Mode or use a 2nd monitor.

Some monitors will support a faster scan velocity than their maximum vertical refresh rate, so you might be able to go much bigger, but you will be limited by the maximum bandwidth of your video cable and the transceivers on both sides (for whatever port you use on both ends -- DVI, DisplayPort, HDMI, and their age/capabilities).

Once you've done all this one-time thing, take a screenshot/photo of your working numbers and post them here along with your monitor model, so that other people using the same monitor model has it.

[mist]

Thanks again!

I set VT 1335 in CRU look screenshot, applying, restarting, but nothing change, total vertical lines is still 1235
https://imgur.com/a/NDoSgH7

Here's a helpful data point: Some of these Samsung 1920x1200 monitors are overclockable to about 72Hz-75Hz

viewtopic.php?f=8&t=5905&p=44690#p44690
maybe i did wrong?

[mist]

Finally applied new VT. Maximum VT value that monitor can handle without stretched picture is 1310. Sadly, but its not help, at top of screen i still see fluctuating
https://imgur.com/a/aQuwCcF

[mist]

Chief Blur Buster Hello! So i am still curious why trick to increasing VT not help?

[Chief Blur Buster]

Chief Blur Buster Hello! So i am still curious why trick to increasing VT not help?

That was only the first step.

Now the next step is you need bigger negative indexes to move the tearline DEEPER into the now-embiggened VBI.

1250 into 1310 is still too shallow. Currently, right now, 1250 and -60 means the same thing in Scanline Sync for VT1310 (1250+60 = 1310) because it's a wraparound effect. But I like negative indexes because they stay proportional to the top edge (preferred) for all modes/resolutions, while positive indexes may sometimes exceed the VT and not work for all modes.

At VT1310, for 1080p, you've got a VBI size of 230 pixels now. So you can use a negative index of 230 instead of a negative 60.

So for the most forgiving hidden tearline, specifically for VT1310 (specifically) try using "-230" for Scanline Sync for that particular VT. Adjust up/down as needed.

[mist]

Today i can set 1320, at 1325 screen is began ripple.

I try set scansync tearline at -230, -240, -220 but in game tearline is upper of 7-10cm at bottom edge of screen. With hotkeys i am put it down. May be all good? But not. Effect from our manipulations is not stable. After restarting game or quit to menu or alt-tabing fluctuating at top is back

[mist]

So, why effect disappearing fluctuating is not stable?

1. Enter to game
2. Alt-Tab
3. Restart RTSS
4. Back to game
5. At this step fluctuating sometimes disappearing totally
6. After quit to game menu, change game map, alt-tab, restart game - fluctuating 100% back again

Why sometimes i see fluctuating and sometimes not?