IOGEAR2-Port Cinema 4K DisplayPort KVMP Switch with HDMI and DisplayPort Out USB 3.0 and RS-232, w/Full Set of Cables (TAA) GCS1932M

I'm using a Dell 27 Ultra HD 4k Monitor - P2715Q at 3840x2160 @ 60Hz. I love the monitor. I have a windows 10 desktop, a linux desktop, and a windows 10 laptop. Obviously, all these connections are display port (out of the dock for the laptop). I'm not using the audio features of the KVM switch so I can't comment on those. My USB keyboard and wireless mouse are typical mid-range, nothing special. Can't comment on the problems people have had with high-end keyboards. Mine work perfectly. I use the double scroll lock protocol to change computers.This is an expensive product, so you'd want it to work perfectly. It doesn't quite. However, with a couple of tweaks, it's nearly perfect.I've had help from IOgear support and am running new firmware that hasn't been released yet. It's called GCS1932_1934_TEST_170519. You may want to see if the work-arounds I mention below solve your problem before working through the layers of IOgear support to get to someone who knows about this firmware and will give it to you. I got the new firmware before I changed the power on detection setting. I can't tell whether I needed the firmware, but they did seem to think it would be helpful for my problems. My problems were always about what happens when a computer powers down a display for energy savings and the KVM doesn't restore the display properly when the computer powers it back up.If all your screens are always powered (you don't have power down on timeout for energy savings), then it does work perfectly as far as I can tell. Once you enable monitor energy saving power down, you get into trouble when the KVM automatically switches to the next computer when the computer powers down the monitor. There is a setting you can change for that (you will have to read the manual to find the procedure to switch this setting to off -- it is called "power on detection" under "advanced settings"). Disable that "auto-switch on power down" and you're mostly home.My remaining problm is this. My windows 10 laptop and the KVM don't agree with each other when I switch away and then back. Sometimes the monitor just goes into low power mode as if the laptop isn't driving, but if I check the display settings on the laptop's built-in screen, I can see that the laptop thinks it is driving the display. It turns out that there is an easy work-around for this case (two actually). Either 1) disconnect and reconnect the displayport cable on the monitor (between monitor and KVM, not between laptop and KVM) and the KVM initializes correctly and the the laptop display returns, or 2) using the monitor settings, switch to another input (e.g., HDMI) and immediately switch back, and the same exact thing happens -- the KVM initializes the connection correctly and you have the laptop display again. I can tell the laptop thought it was driving the large display the whole time because the windows and desktop icons haven't been moved the way they would be if I actually pulled the displayport connection from the back of the laptop. Windows responds to the screen size by moving things around.As an added note, if the laptop is set to power down the display after some time for energy savings (as mine is), and you switch away from the laptop and don't switch back until that time has passed (so the laptop will have powered off the monitor it thinks it is connected to), then switching back to the laptop always works correctly (with a minor delay for some reason). The only real problem is switching to the laptop when it thinks the monitor is powered on and you have actually been connected to a different computer using the KVM. That's when I use the trick of switching input source on my monitor to HDMI and back to DP (using monitor control buttons) and the screen comes back up.I do not have the problem with the desktops, but only once I disabled the auto-switch feature (in other words, I did have problems before that, possibly related to the original firmware).My screen is gorgeous from all three sources and I'm very happy with the KVM in general.All the cables needed (even audio) came with it and are all very decent quality.This KVM is expensive but less expensive than two other choices out there and who knows what quirks they would have. The others cost the same or more and don't come with cables so your total cost can be a lot more.

I use this switch with my  Dell 27" 4K HDR Monitor  and four computers: 2 desktop PCs, 1 laptop PC, and 1 Mac Mini. It took a little tinkering to get it set up but it's worked flawlessly since. It's really nice to be able to use standard cables and run USB3 everywhere. Once you get used to 3840 x 2160 HDR @60Hz it's really hard to go back.A few notes for potential owners:- Use quality video cables! DisplayPort seems to be kind of touchy about cables and connectors. Use a cable that your setup doesn't like and the image may flicker or the monitor may not sync to your computer. The cables that came with the switch are fine for short runs but if you need to reach further I've had good luck with  Accell DisplayPort 1.2 Cable with Locking Latches .- I use a programmable gaming mouse with extra buttons. I needed to activate the switch's "Mouse Passthru Mode" to get my PC to recognize the extra features.- You can tailor many aspects of the switch's operations by various keystroke combinations -- be sure to give the documentation more than a casual glance.- I ran into a glitch setting up the switch so I flashed the device's firmware. You may want to do this if you run into problems -- it's easy to do by following the directions on IOGear's web site. It's been rock solid ever since.

If you are not technically inclined, you may have trouble with this switch, as it has some caveats that you need to account for. That said, this is otherwise a very good KVM switch with excellent features (though I haven't figured out all of them yet). The user manual is available in PDF if you find the booklet in the box is not enough, but don't expect much from IOGEAR's tech support line. Not only will you get voicemail all hours of the day, but when you submit your issue online they do not respond. At. All. The switch works quite well however, and I do recommend it if you are able to troubleshoot issues on your own.The included DisplayPort cables are trash, though. Sure, they look/feel good, well insulated and thick, but they are not DP certified and you will find yourself with flashing/blinking monitors, especially if you're using laptops connected to docks. Unplugging the monitors from the switch and plugging them directly into the dock makes the flashing/blinking go away. My monitors are not 4k, so I was not overdriving the switch or the DP channel from the computer. At first I thought the issue was the switch - I updated firmware, etc., but then I decided that maybe certified cables (found here: https://www.amazon.com/gp/product/B083C3ZZ9X/ref=ppx_yo_dt_b_asin_title_o05_s00?ie=UTF8&psc=1) would do better. In short, they did, and the issue is completely gone. Do yourself a favor and buy certified cables.I consider the cabling issue to be a minor issue, but that with the tech support issue cost a star. It still rates 4 stars because the switch is good quality and solid. Since getting the right cables, I have had zero issues with it. I do wish it would keep the EDID information on the ports of the computers you switch away from, because when you switch to another computer, the first computer then moves all of your open windows to the primary dispaly, and doesn't put them back when you switch back to that computer. This is annoying, but not the fault of the switch so much as a DisplayPort and Windows issue. I expect I'll eventually find a work around for this.Anyway, the switch is quite good, and allows you to use MST/daisy chaining on your monitors, through the switch, and to your computer or dock, resulting in fewer cables being used at the desk, which makes for a bit neater workspace, allowing me to indulge my inner zen. If you're looking for a good KVM, this is a good candidate, just remember to buy certified cables and avoid the ones included in the box.