Help identifying Gsync/monitor issue (faulty monitor/gpu?)

[TTT]

I've posted a few times about having input lag trying to use my monitor (XB252Q) and I am slowly getting somewhere but still I'm not sure what is happening with the settings I'm trying out.

I use Fortnite to jump in and out of because its quick and I can easily tell if input lag is present. (Always with vsync off in game)

So I set up the monitor exactly how the Gsync 101 tells me to and I have pretty big input lag, but at completely random times it goes away but never stays away. ( You can tell its not right because the movement isn't fluid with the mouse at all, the sens feels way lower and its half impossible to aim, it just feels completely off.)

I have tried forced vsync on and off in NVCP and also on no frame limiter in FN/ also tried the other limits and doing the custom 237 limit, its all the same input issue.


Now to the point where I have now figured out a setting which seems to make it feel way more fluid but don't quite know why..

If I turn the Vsync mode onto the default setting of 'Managed by 3D application' and keep vsync off in game it seems to stay fluid and feels way better.. But surely forcing Vsync off or on and staying under the refresh is the same as managed by the game with in game vsync off, so why is the other setting causing lag?

Also I found the input lag went away if I forced vsync off in NVCP but turned vsync on in game.

Also I have been having some issues with my pc, I can randomly hear a fan getting loud under no load, sometimes there is a rattling/virbrating sound with it. The PC freezes browsing Firefox and sometimes opening task manager and other programs. Still happens after Windows clean reinstall.

I have just recently read this can be signs of a faulty GPU, so potentially that is the problem?

Also my monitor has some kind of fault with a line of pixels randomly appearing on the screen, its only happened a few times but in Lagom pixel inversion test you can see it. I can't seem to find anybody else online with the same issue.



Sorry for the long post but I am pulling my hair out trying to find out whats wrong. I've not done this testing with gsync off yet, so it might not even have anything to do with Gsync but there is definitely something wrong!

[Chief Blur Buster]

This post slipped my radar (apologies!), but have you fixed this yet?

Fixed-position vertical issues like these are typically RMA. Vertical bands that never move horizontally -- such as being affected by window draggin -- like this one may be a result of a defective LVDS ribbon cable that attached to the panel. Or some failure with electronics embedded in the panel. I would consider this an RMA.

TIP for troubleshooting: Big giveaways of LVDS defects (and/or segment issues such as panel driver defects) if if the vertical band are an integer divisor of screen width, e.g. exactly 1/16th of screen width, or exactly 1/2 screen width, or exactly 1/8th screen width, etc.
And especially at integer-divisor horizontal positions (e.g. left edge of vertical band exactly 5/8ths from left edge of screen, or only affects left half or right half, or is a 1/16th band in the 11th position out of 16 bands, or whatever -- band width behaviours varies from monitor to monitor -- etc). These band issues are generally unfixable by the end user, although an out-of-warranty monitor may be fixed by opening monitor and carefully jiggling internal connectors (less than 25% success rate without a soldering iron or precision work because the defects are often not in the connectors)

Definitely not GPU for this type of issue. And the fan in the PC would have nothing to do with this specific artifact on the screen, so you are likely troubleshooting very separate issues in this situation.

An overheated monitor may cause intermittent band behaviours as a single segment may start failing before others. So make sure you don't have a heater blowing into the back of the monitor.

[TTT]

This post slipped my radar (apologies!), but have you fixed this yet?

Fixed-position vertical issues like these are typically RMA. Vertical bands that never move horizontally -- such as being affected by window draggin -- like this one may be a result of a defective LVDS ribbon cable that attached to the panel. Or some failure with electronics embedded in the panel. I would consider this an RMA.

TIP for troubleshooting: Big giveaways of LVDS defects (and/or segment issues such as panel driver defects) if if the vertical band are an integer divisor of screen width, e.g. exactly 1/16th of screen width, or exactly 1/2 screen width, or exactly 1/8th screen width, etc.
And especially at integer-divisor horizontal positions (e.g. left edge of vertical band exactly 5/8ths from left edge of screen, or only affects left half or right half, or is a 1/16th band in the 11th position out of 16 bands, or whatever -- band width behaviours varies from monitor to monitor -- etc). These band issues are generally unfixable by the end user, although an out-of-warranty monitor may be fixed by opening monitor and carefully jiggling internal connectors (less than 25% success rate without a soldering iron or precision work because the defects are often not in the connectors)

Definitely not GPU for this type of issue. And the fan in the PC would have nothing to do with this specific artifact on the screen, so you are likely troubleshooting very separate issues in this situation.

An overheated monitor may cause intermittent band behaviours as a single segment may start failing before others. So make sure you don't have a heater blowing into the back of the monitor.

I ended up getting the panel replaced from Acer. I've still not figured out the intermittent input lag issues though. Just posted another thread with a new issue as well.