New DP KVM solution

I’m just entering the world of DP, having been on seperate DVI/HDMI connections until now. I plan on moving to two larger 4k DP monitors, and getting a KVM switch.

Anticipated hardware:
Geforce 770M
Geforce 760GT
Intel Graphics in a Thinkpad X1 Carbon (work issue)
TBD Ryzen 4000 series notebook

I know that most of the Ryzen notebooks I’m looking at only support MST via a single output, and I think the Thinkpad configuration is the same.

What is the best approach here? Do I just get a single display KVM and chain the monitors directly? Do I need one of those MST break-out boxes to connect the monitors with the switches, etc?

While the Level1 stuff looks great in general, the USB3 aspect is mostly useless to me (just need switched keyboard/mouse and maybe webcam). I’d be open to something else if it seems like a better fit.

Thanks in advance for your thoughts!

The reviews I remember seeing for StarTech are hit and miss but there is the StarTech SV231DPDDUA2

Welcome to the community

I use a pair of Dell 1440p monitors with daisy chain MST over dp1.2. that works great as a single cable solution.

Your alternative is to invest in a TB3 or usb-c dock with two do outs. A Lenovo one would likely work best given your ThinkPad. See if work will subsidise.

If all you are doing is swapping laptops the easiest solution is to dock and undock via that usb-c cable to swap displays. If however you add a desktop in there or add keyboard and mouse, then you may want to invest in a decent KVM.

Note driving two 4k panels from vintage laptops is hard work. Check your hardware can cope before you invest big money.

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Pretty much

Good option for this

Black Box do a KVM that will switch dual 4K 60Hz displays and has true EDID emulation. The price is a bit scary though :frowning: (and shows what good value the level1 units are.

L1T is 4k 120 (well that one, the 1.4 ones)

First, thank you all for the responses.

TB3 is not really an option for me. It is Intel only at the moment, and likely disabled like other peripherals on the work machine (the only device that would support TB3 hardware).

USB-c is not really an option for everything, so I can’t just move a single cable around. Only the future Ryzen laptop and the newer Thinkpad X1 Carbon (not sure which one they will send) are likely to support DP over USB-C, anyhow. Definitely not the desktop.

After the comment about older laptops, I went looking more closely, and DP 1.2 MST on two 4k monitors is going to be capped at 30Hz refresh. That’s not a big deal for my work laptop, but it is for the others. In this price range, I’m looking to stick with the same hardware long-term.

The Startech unit linked seems to be only 2 port. I found a 4 port dual DP unit, but it looks like only DP 1.2:

I looked for the Black Box unit, but seems to be limited to DP 1.2 (and yes, really pricy for what you get).

Level1 has DP 1.4, but it’s not yet available in a 4 port. It’s still a good ways off, right Wendell?

This is the only kvm series I found thus far that seems to meet my 4 port DP 1.4 requirement. It’s dual port (a plus long-term), and seems to have EDID, DDM, and hotkey support:

Does anyone have experience with that unit or similar models from connectpro? It’s definitely expensive, but I’m also going to be at this workstation for 50-55 hours every week.

Thanks again!

So this puts you in a sticky situation. See, displayport is a very sensitive signal and as is, with any KVM, you sort of run to the edge of the signal quality threshold. If you add in additional length and componentry, by way of MST, you might degrade the signal too far and wind up out of luck.

I don’t want to discourage you, just make you aware of the issues I’ve encountered in the past.

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If you add in additional length and componentry, by way of MST, you might degrade the signal too far and wind up out of luck.

Is that true for mostly all MST devices in a chain, or just the inline breakout stuff? For example, does monitor-to-monitor daisy-chaining pass through a mostly passive signal as well? I was under the impression that my signal path was only to the first monitor.

From a windows standpoint I wish the lvl1 had edid but I guess that really jumps up the price and can of worms of problems. With Linux the windows do not get resized when switching. Overall love that I got this lvl1 KVM before covid, I’m using the heck out of it now.

That’s a good question.

I had two Dell monitors that supported chaining, and it worked, but I also have a powered MST splitter where it didn’t work. So I think it really depends on how your system is set up.

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In my case, the whole KVM path came about due to the work issue Windows laptop. I was otherwise perfectly happy going through my Linux desktop for everything before (all Linux).

The only real catch was my lone Windows VM (with PCI video passthrough), which I needed for firmware flashing. If that VM crashed while the system was up, it would take down the whole box. The individual at Line6 that decided firmware flashing requires a hardware OpenGL UI needs a wake-up-call.

Someone made a script that would restore all the windows windows (lolz) to their size and position but it stopped working a number of win10 updates ago, also I wouldn’t install it on my work laptop. Wish win10 had a setting for this.

if you really want edid, the repeater works really well for that. Currently limited to dp1.2 though. If you’re buying more than 1 I can send you a coupon :smiley:

You would not believe how hard it is to maintain perfect dp1.4 signal integrity. Everything cheap would add an undesirable amount of latency, or has other side effects. We might not see a 4 port next year, even. The last sets of 1.2 have way higher signal integrity than the earlier model 1.2, but it’s still just… not a great situation out there for this type of silicon. Built-in repeaters of some type is prettymuch what anyone would have to do, so far.


If I were a content creator id get one or two, bit pricey solution for two win boxes x2 monitors. But a great price compared to plain DP passthrough emulators. HDMI has much better prices units- uhhhg

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