Screen flickering on 165Hz after powering off the KVM switch

Hi there,

first of all I would like to mention, that I’m very happy with your KVM product. It worked perfectly fine since the beginning :slight_smile:

I have one weird issue which I hope you will be able to explain to me.

To save some power, I attached my 3 monitors and the KVM switch to a power plug that I can turn off over night. In the morning I power on the plug again and afterwards start the computer. One of my screens (1440p@165Hz) starts to flicker badly in this case. The other 1440p@60Hz screens are fine. I already exchanged the cables to Club3D ones, but this didn’t solve the issue. Reducing refresh rate to 60Hz on the affected screen seems to mitigate the issue as well in these cases.

I can live with just powering off the screens and leaving the KVM powered all the time, but I was just wondering what might cause this issue.

cc @wendell @Level1_Amber

Does the flickering last for a period of time then fix itself?

Do the club 3d cables have ferrite clamps near the end? (Can Google that, looks like a plastic cylinder).

You might need to add one or two of those to the mix.

Displayport goes through a training process and when it’s flickering it has trained to a weaker level when it needs a stronger signal level. When it’s working normally it’s triained to the stronger level. Ferrite clamps can help squelch outside interference and force training.

Total cable length can also matter even with club3d. Some LG and Samsung monitors stupidly save too much power in power save mode, see if you have an osd option to disable eco mode

This is what he’s talking about:

What is your total cable length?

I didn’t wait for a longer period to be honest as I had to get some work done, but I played with the refresh rate settings for about 5 minutes and after switching back to 165Hz, the flickering was still happening.

It does not look like the have these. I’ll buy a pair and give it a try, thanks :slightly_smiling_face:

It’s about 5 meters.

Thats borderline. If you need that much length try fibbr fiberoptic cables, or swap in a 1 meter club3d cable on either side.

I’m still waiting for the ferrite caps to arrive. If these don’t help, I might try out the optical cables (can’t use shorter ones sadly). For now it seems like 144 Hz works pretty well compared to 165 Hz. I can live with that, if it’s reliable.

Just fyi: The ferrite caps didn’t do the trick, but I think my panel might have been defective. I recently upgraded to a new monitor and this one is flicker free even on 10-bit HDR UHD @ 160Hz. Might as well be that the old screen did not use DSC and therefore consumed more bandwith than the new panel at higher specs.

Anyways… everything working fine now :slightly_smiling_face:

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