Scid 5.1 + Intel graphics: whole-screen brightness pulsing with two instances — anyone else?

[Jonathan003]

I have been chasing an odd display problem for a long time, and Scid is the most reliable way I have found to trigger it. I do not think Scid is at fault — I suspect the Intel graphics driver — but I would like to know whether other Scid users see the same thing.

WHICH SCID

Scid 5.1, downloaded from https://github.com/benini/scid
(Fulvio Benini's Scid — not Scid vs. PC.)

THE SYMPTOM

The whole screen slowly pulses brighter and darker. Text stays perfectly sharp. No jitter, no black flashes, no lines, no tearing. Everything on screen pulses together, including Task Manager, so it is not one application redrawing itself.

It comes and goes on its own, and some episodes are worse than others.

THE TRIGGER

Opening two instances of Scid starts it reliably — not every time, but often. Running a browser with streaming text plus a command line tool at the same time can also start it.

Two details that puzzle me:

- GPU utilisation sits around 3% during an episode, so it is not a load problem in any obvious sense.
- Closing Scid does not stop it immediately. It fades away over several minutes.

MY SYSTEM

HP Pavilion All-in-One 32-b1015nb, 31.5" 4K internal panel at 60 Hz
Intel i7-13700T with UHD Graphics 770 — this drives the panel
NVIDIA RTX 3050 Ti also present, but not connected to the panel
Windows 11 Home 25H2

WHAT I HAVE RULED OUT

- Intel graphics driver updated from 31.0.101.5186 to 32.0.101.7088 — no change
- BIOS updated F.07 to F.19 — no change
- Windows HDR is off
- Variable refresh rate and dynamic refresh rate are both reported as not supported
- Windows has no "change brightness based on content" setting on this machine
- Intel Graphics Software has no Power section on this system
- Stopping the Display Enhancement Service while it was flickering changed nothing
- The registry fix FeatureTestControl 0x1200 to 0x1210, which disables Intel's display power saving, did not fix it. The flickering came back while the value was still set.

I am currently testing a second registry value, DisplayFeatureControl 0x3E7 to 0x3E3, which is supposed to disable Intel's contrast processing. Too early to say.

ONE USEFUL TEST

If you want to check your own machine: put a large pure white area, a mid grey area and a pure black area on screen at once, and watch during an episode. If white pulses too, the backlight is moving. If only the grey moves, the picture is being reprocessed and the backlight is steady. That distinction points at completely different causes.

MY QUESTIONS

1. Does anyone else running Scid 5.1 on an Intel integrated GPU with a built-in panel — all-in-one or laptop — see this? Reports from Scid vs. PC users are also useful: if it happens there too, it is not something specific to this build.

2. Does it matter what Scid is doing? Two idle boards versus engine analysis running in one or both?

3. Has anyone found a fix that lasted?

Any data point helps, including "I run two instances all day and never see it" — that would tell me something too.

Thanks.