USB dock or KVM switch?

Question

I just got a new PC at work (HP Z2 with Win10 x64), but for legacy product support I need to maintain a legacy machine (Dell Optiplex 9010) with Windows 7 x64 and x86 as well. IT was having issues getting drivers for Win7 x86 and x64 for the new PC, so dual-booting isn't an option. So I need some sort of switching mechanism to go back and fourth and use the same keyboard. mouse, and monitors.

Traditionally, I would assume I'd use a KVM switch and be done with it. But I was thinking it'd be cool to get new monitors with DisplayPort 1.2 so I can daisy-chain my monitors and reduce cable clutter. As it is, I'm an embedded software engineer, so I've got plenty of loose wires and my desk will go from clean to this in a day if I'm not careful. But then in doing my research, with the rise of USB 3.0 and whatnot, it seems like KVM switches are giving way to display over USB. I'm seeing DisplayLink thrown around as well. I'm not sure how much can really be displayed over USB and how many monitors it'll really support and if I'm still limited by (or dependent on) my graphics card at all.

I'm not opposed to hardware upgrades (monitors, graphics card, etc). I actually need to replace one of my monitors, so I may as well replace both and get matching ones, I currently have two Dell P2411H monitors. The New PC has a NVIDIA Quadro P400 inside, old one has an AMD Radeon HD7570 (which I'm not opposed to upgrading if needed). But now I'm even seeing that DisplayLink operates over plain old USB2.0, I was thinking I needed to add a USB 3.0 card to the old PC to make it work.

I'm not doing anything graphics-intensive, I don't need 8K video and a monster graphics card and whatnot. Mostly trying to reduce cable-clutter as much as possible. Any help is appreciated.

Answer 1

Oh, wow, you found the right person to ask. Because I spend ~14 hours today, trying to get DisplayLink to work with 4 additional monitors over USB 2.0. So I can tell you the experience firsthand.

The first thing I'll point out is, that DisplayLink is fairly slow at multiple monitors. So my Ultra HD monitor loads much quicker over DisplayLink, than two 1024x768 monitors. Over USB 2.0, the first .4 seconds of motion the response is good, after that there's about 0.15 second lag (e.g., if I'm dragging a window, I often overshoot). It seems that the cache to update the image gets full. Even if the other window is blank, and doesn't change at all. The performance over USB 3.0 is better.

That being said, two things to keep in mind. One, if all you're doing is writing code (or anything that doesn't erase a bunch of pixels at once), then you should be fine. And two, the difference between 2 monitors and 4 monitors is negligible. It seems the main cause of lag is for it to figure out which monitor to send it to, versus simply sending the image directly to the monitor. Considering the uHD performed that much better, I think tomorrow I'll spend figuring out how to make Windows treat the multiple monitors that I have as a single monitor.

And now, the good side. The best part of DisplayLink, is their support for old hardware. I have a generic graphics card from 2003 or so, and DL now has a version that works with it. I have tried several different companies online, until I saw someone sell a "will work guaranteed" adapter online for $500. It turns out their have direct access to DL's developers (in UK, I believe) -- so they corresponded with them, DL sent some diagnostic software, and lo and behold -- in a few months they came out with a version that works for my graphics card.

Also, the reliability of DisplayLink is simply amazing. I run DL software on 6 computers in my family, and there was one that would give black screens occasionally. They sent one diagnostic software, which generated a report and I sent it back to them. They sent another diagnostic tool, another report, and they told me I had to send them back the screen, which they programmed with another firmware, and mailed back to me. Bottom line, DL is committed to reliability, and in a more complicated setup, I'd choose it over KVM any day.