AVE10N
Before anything technical — what you're describing sounds genuinely exhausting. That's a lot to deal with. I've been through this myself, more than once.
I've looked into the source code of novideo_srgb — nothing unexpected there. To control dithering, it calls the Nvidia driver through the NVAPI function NvAPI_GPU_SetDitherControl. It doesn't interact with the hardware directly. So the application itself couldn't have permanently changed anything at the hardware level.
Everything below is just a hypothesis — I want to be upfront about that.
The issue might be related to BVD and how dithering works at multiple levels on your GPU.
There are several levels where dithering can be active, and novideo_srgb only controls one of them:
Level 1 — the NVAPI setting (what novideo_srgb manages). By default, the driver controls dithering depending on color depth, format, and dynamic range. This is software-controlled dithering in the driver.
Level 2 — part of the display engine itself. It only activates when the driver is fully loaded, and on some GPUs it reportedly can't be turned off through software. When the driver isn't loaded, both layers are inactive — but for different reasons: Level 1 simply isn't running, and Level 2 isn't active because the display engine pipeline hasn't been initialized.
One possibility: Level 2 was always there, but your eyes and brain didn't notice it. After exposure to temporal dithering, your visual system may have become sensitized to the background dithering that was already present.
This kind of persistent neurological response — where symptoms continue even after the original trigger is gone — is consistent with BVD. It's a condition where the visual system is under constant strain to maintain binocular fusion. This mechanism is particularly sensitive to high-frequency or asynchronous changes in the visual field, exactly the kind that temporal dithering creates. The visual cortex processes this flickering, but with BVD the strain can build up significantly — and symptoms can persist for some time after exposure stops.
Another possibility: some setting is still enabling or amplifying Level 2 dithering without you realizing it. But if the symptoms started before you reinstalled the OS and drivers, that points more toward a neurological reaction than a misconfiguration.
The fact that a different Nvidia card worked fine could also fit — different GPU models can have different hardware dithering implementations, or none at all.
There's also a third option: something subtly different in the Nvidia driver you downloaded, even if the version number matched. But it sounds like that's probably not your case.
For now, the neurological reaction hypothesis seems the most likely explanation.
P.S. A few things worth trying, just to rule things out: Linux, the card in a different computer, different driver versions, and different settings. For example, on "Limited" range, the driver performs a color conversion and may enable dithering to compensate — switching to "Full" range could make a difference. It's mostly trial and error from here, but small changes can sometimes help narrow things down.
P.P.S. If nothing works out, selling the card and finding a replacement might be worth considering — people here on the forum can help with that. I should mention that my experience is mostly with Apple hardware, and my knowledge of Windows GPUs is limited. I'm currently using an RX 6600 on PC, which is probably weaker than your RTX 3060, so I may not be the best guide on the Nvidia side of things.