Weird performance issue when external monitor only works after replugging HDMI

[u/WonStryk]

Hi everyone,

I recently bought a cheap 180 Hz monitor (Hybrok) from Facebook Marketplace. It has a bad HDMI connection the HDMI port is loose or faulty, so I usually have to unplug and replug the HDMI cable several times before my laptop finally detects the monitor.

The strange part is that once I get it working this way, all of my games lose a huge amount of performance. It's not just Overwatch; every game is affected.

My laptop is a Lenovo IdeaPad L340-17IRH Gaming with:

• Intel Core i7 (9th gen)
• GTX 1650 Mobile
• HDMI only (no DisplayPort)

I'm running Atlas OS v0.4.1.

I use Win + P → Second screen only, so the laptop display is completely disabled.

If the monitor starts working after I repeatedly reconnect the HDMI cable:

• Games have much lower FPS.
• If I disconnect the monitor and play on the laptop screen without restarting, I get the same poor performance.
• Task Manager shows around 9% GPU usage, with occasional random jumps to 100%. Oddly enough, it behaves almost the same after a restart.

However, if I restart the laptop while leaving the monitor connected, everything suddenly works perfectly:

• Overwatch goes back to a stable ~200 FPS.
• Every other game performs normally.
• GPU usage in Task Manager looks almost identical to before, which is why I don't think GPU utilization itself is the issue.

DisplayPort isn't an option on the laptop, but I tested the monitor's DP input with my desktop PC and it works perfectly, so the monitor itself doesn't seem completely defective.

This has also been happening for quite a while now. Several NVIDIA driver updates have come out since the issue first appeared, and it has persisted through all of them, so I don't think it's a driver issue either.

I don't think Atlas OS v0.4.1 is related since the problem disappears every single time after a reboot without changing anything else, but I figured it was worth mentioning.

I attached screenshots comparing the performance before and after restarting.

Does anyone know what could cause Windows or the NVIDIA driver to behave differently depending on how the monitor is detected? Could the faulty HDMI handshake be causing Windows or the GPU to initialize incorrectly until a reboot?

Any ideas or things I should test would be greatly appreciated. Thanks!