1.4 Display Port KVM Switch - Dual Monitor - Four Computer - Setup Help!

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Greetings!
I’m a new owner of a Level1Techs 1.4 Display Port KVM Switch - Dual Monitor - Four Computer 10gbps.
My current setup is as follows:
Monitor:

  1. Samsung Odyssey OLED G9 - G95SC

Devices:

  1. Personal PC: RTX 3080 + AMD Ryzen 9 5900X Running Windows 10
  2. Work PC: RTX 3080 + AMD Ryzen Threadripper PRO 3975WX Running Windows 10
  3. Work Laptop: 2021 M1 Macbook Pro 16"
  • The KVM is connected to the monitor via a 1M Club3d Displayport 1.4 cable
  • Both PCs are connected to the KVM via 2M Club3d Displayport 1.4 cables
  • The laptop is connected to a 1M Club3d Displayport 1.4 cable to a Cable Matters USB C Multiport Adapter (USB C Hub DisplayPort 1.4)

Currently I’m experiencing a few issues that I would appreciate help resolving.

  1. After switching away from my personal PC and then returning, the display never returns. The only solution I’ve found is to restart.
  2. My work PC display signal appears to break down above 60hz. The output jitters and periodically goes black. [UPDATE] This appears to be solved after adjusting settings in nvidia control panel
  3. Laptop display signal also seems to be incredibly weak, even more so than the work PC. Similar but pronounced symptoms observed. I tried bypassing the USB C to displayport adapter and using a Maxonar USB C to DisplayPort • 8K 60Hz Type C to DP Cable which works when plugged directly into monitor but no displays are found in the settings.

Please let me know if there are any additional details I can provide, thanks for your help!

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Hi! Thanks for reaching out. Hopefully we can solve your issues :slight_smile:

I’ve seen this issue. When you switch from a different pc channel, back to this one, does it come back?

Ex: PC1 is black → switch to PC 2 → Switch back to PC1

You just need a better cable here, probably. That particular one might be dodgy. You could get a fiber optic cable to solve this issue probably if the Nvidia settings don’t seem to permanently solve it, or try exchanging that one.

Is the laptop connection USB-C → DisplayPort, or DisplayPort → USB-C? Can you clarify how it’s hooked up?

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No, it doesn’t :frowning:

Can you recommend a fiber optic cable?

I’ve tried 2 approaches.

  1. 1m Club3d Displayport 1.4 cable → Cable Matters Usb C Hub → Macbook pro
    • This yielded low signal output with jitters and blackouts even at 60hz
  2. 4ft Maxonar displayport 1.4 to usb c cable → macbook pro
    • No video signal detected
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I’m a little confused by how you’re listing the laptop connections. I think they’re backward? The MAC is the video source, so naturally, it would go first in the chain:

  1. Mac Pro (USB-C Out) → USB Hub (USB-C In)
    USB Hub (DisplayPort Out) → KVM (DisplayPort In)

  2. Mac Pro (USB-C Out) → KVM (DisplayPort In)

?

These cables and their source-destination direction are very important for troubleshooting lol

For option 2, quality USB-C to DisplayPort cables are very difficult to find and do not go both ways. We recommend the Moshi USB-C to DisplayPort cable specifically. It’s a little pricey, but the quality is worth it:

I looked up the cable you mentioned, the listing looks like it should probably work, but I have no experience with them. The reason Wendell recommends Moshi is because it’s one of the few he’s tried that work as intended.

Also, I’m a little skeptical of the cable. Having no display output is strange.

Can you try changing your resolution down to 1440p@60, then swapping to the USB-C → Displayport cable? It might be that the res & refresh rate is just too high so nothing is being displayed.

Sure :slight_smile: Wendell recommends FIBBR. Fiber optic cabling is special because it’s basically lossless quality. Instead of copper (which degrades over distance) there’s glass/laser magic involved to keep it strong over loooong distances.
https://www.amazon.com/FIBBR-Ultra-High-Speed-Cable/dp/B0C3CT6D6W?th=1

5

This is the current setup, sorry for the confusion!

For what it’s worth, the cable works fine when plugged directly into the monitor, but I’ll try reducing the refresh and report back.

Anything I should be trying to fix the switching issue with my personal PC?

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Oh right lol I meant to comment on that. I’ve seen this happen a few times, it’s usually either:

  1. DDU and reinstall the nvidia graphics driver
  2. Disable the sleep-related setting in your monitor’s OSD.
  3. Update your monitor’s firmware. I have a guide if you need it.

Here’s your monitor’s manual if you need it as well:

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@wendell any insight on the sleep bug happening on a Samsung G9? Not Neo, but widescreen nonetheless.

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I just tried this, no luck :frowning:
Additionally, I tried plugging the usb c hub displayport directly in the monitor and was able to get full resolution at 120hz.

  1. Okay i’ll give this a shot
  2. I can’t find any sleep related settings, can you be more specific?
  3. I’m on the latest firmware.
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Does that port of the KVM display if you swap cables around? Meaning, if you try your DisplayPort PC into that port instead, does it work?

Look for something to the effect of eco mode or power save mode, you’ll want to disable that

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Does turning the monitor off and on wake the display up?

If you cycle through the inputs quickly will the display return? Or is it after a few minutes?

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So i swapped to the empty port on the switch and it improved slightly. I took a video of the jitter and cutout if it’s at all helpful.

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This solved the switching issue. Only problem that remains is the macbook connection!

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Woop! One down. I’ll see what Wendell thinks

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[UPDATE]
I added a Club 3D DisplayPort 1.4 Active Repeater between the USB C hub and the KVM and that has resolved the problem.

Side note: Do your KVMs do any hardware signal boosting? Would that be something you guys would consider adding?

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Nice! We’ve had a few people give success reports with those active repeaters.

Unfortunately the answer is no, and no. Signal boosting or anything of the sort would ultimately cause more problems/compatibility issues. The KVM does not manipulate/control/change the signal in any way. Doing so would interfere with variable refresh rates and all kinds of stuff. The goal of the KVM is to be as invisible as possible, therefore it is as universal and compatible as possible with any new hardware and firmware that may come out. Basically, modifying the signal opens up a whole can of worms that come with their own problems. It’s better to not, and find fixes for the minor outlier issues.

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