IOGEAR4-Port HDMI 4K KVMP Switch - 2-Port USB 3.1 Hub Transfer Rate 5Gbps - 4K 60Hz - Control 4 Computers w/1 Keyboard Mouse - HD Audio - Auto Scan Mode - TAA - Mac/Win - GCS1934H

This is just what I needed to be able to use my personal computer, personal laptop, and work computer(s) with my 4K screen, high-def mouse and mechanical keyboard. It works well most of the time. Switching via the keyboard is easy. Sometimes the lag between switching and the screen displaying is longer than I would like. There are also times (I cannot deduce the sequence of events that leads up to it), when the keyboard and/or mouse is not functional after a switch. At first I panicked and unplugged everything. But eventually discovered that the easy (and first option) fix is just to toggle it back to a different machine, then back to the desired one.I really like the extra USB port (although I wish it (or another one) was on the back. I plug my web cam into that port and it is therefore available to all four machines.I cannot comment on the audio features. Since the display is HDMI, I just use the audio from that.(I plug the headphone jack from the monitor into the external audio system input for better audio quality.)

I've tried 3 other cheaper KVMs. Out of the box, this is the first KVM that has worked well between my two MacBooks. Fully switching all peripherals from one laptop to the other takes about 6 seconds. This is pretty slow, but IT FULLY WORKS for my devices, and I never need to rapidly switch back and forth between the two laptops anyway. I would recommend this KVM!The only downside is that the audio output of the KVM seems to be about 50% quieter than from the source laptop. This is true whether I use the output on the back port or the front port of the KVM. Plugging headphones directly into either laptop delivers the full volume I expect. I'm not sure why the KVM doesn't just pass the audio straight through with the same volume.

I bought this to use in my home office to switch between my business laptop and my personal computer without having to change inputs on my displays all the time and to simplify the cabling. For reference, my laptop is a Microsoft Surface Pro 4, with Surface Dock, and my personal PC is an Intel NUC NUC6i7KYK. I have 2 Samsung S27H850 QHD displays running in a Displayport 1.2 MST daisy chain configuration. Each of my computers works perfectly when connected individually via the DP-In to the first display (which then connects to the second via the DP-Out port) ... no problems at all with the daisy chain. When I first connected up the IOGEAR KVMP, I got no display output on either system. After troubleshooting a bit, I found that for some reason my displays were both set to 2560 x 1440 at 59Hz, rather than 60Hz. So I changed them to 60Hz, and this finally brought my NUC screens to life. Nothing on the Surface Pro yet, but I'll get to that. When connected to the NUC, the displays constantly glitched, flickered and went blank completely every few seconds... completely unstable and unusable. On my Surface Pro, I moved the DP cable from the dock to the DP on the side of the Surface, and this finally brought the screens to life for it too. At this point it actually seemed stable, both screens behaving as expected... so I thought great, at least one system is working ok. So I switched back to my NUC to troubleshoot. Tried various things, removed and reconnected the DP cable, swapped the DP cable out for a brand new one, rebooted, checked video driver versions... all good. But still the displays are unusable due to the instability. So I switched back to the Surface Pro. Only screen 1 lights up, screen 2 stays asleep. I pull the DP cable out and plug it back in and both screens come alive. Good right? Nope... a toggle back to my NUC and back to the Surface Pro and Screen 2 is dead again. At this point I get onto the IOGEAR support site. I found a slightly newer firmware for the KVM. Applied it... no difference. I finally decide to contact IOGEAR support, feeling I've done all I could on my own. They initially suggest my systems are not compatible with what I'm trying to do.. to be fair, this is a logical conclusion with no other information... but of course they are compatible... each of them does what is expected without the KVM. Eventually support concluded that it was possible my KVM unit was faulty, and that I should return it to source of purchase (Amazon) and get a replacement which they sent me immediately without me having to return the first one in advance (thanks Amazon!). I've plugged it all back in and EXACT same results. Both of these units are now back in their respective boxes and ready to be shipped back.So I decided to buy the other DP KVM unit that I was considering alongside the IOGEAR one when first looking around. This is the Startech SV231DPU34K. I went with the IOGEAR because it actually included a full cable set, even thought it was a bit more expensive. I just got home with the Startech unit, and plugged it all in and EVERYTHING JUST WORKS!! No messing around... no unplgging/replugging in... just works.So, in conclusion... who knows if the IOGEAR unit will work for you... all I know is that it didn't for me, and all I was trying to do was use it for it's intended purpose. It's an expensive KVM for a high end setup, not some cheapo $50 bus powered device. Standards are standards for a reason, so it should work regardless. Startech has come through out of the box, so worth considering if you are looking for a DP 1.2 KVMP solution.

Paying about $300 more than other solutions was a tough pill to swallow, but the other KVMs weren't brands I was familiar or comfortable with. The only thing I'd remind people of is to disable the mouse and keyboard emulation if you want to use features specific to your mouse and keyboard (extra buttons on your mouse, media keys on your keyboard). (I assume doing this for the keyboard would prevent the KVM from detecting keyboard based switching -- in my case I just disabled mouse emulation.)

Decided to step up to a 4K monitor from a 1440P one, and needed an equivalent KVM. Works great on balance and very similar to my previous IOGEAR KVM's -- once one gets used to switching machines via the keyboard -- it is difficult to except less. Only things to note: occasionally (once or twice a day usually, the monitor will appear to lose sync with the machine, but in a couple of seconds it will come back), with 4K resolution, higher quality cables are required, and lastly, it appears to work best with PC (as opposed to Mac emulating) keyboards, as the Function key and media keys don't appear to work properly, although they do work for PC emulating mode.

Pros:EDID works, so Windows don't get rearranges in a multi-monitor setupSwitching takes about 4 secondsKeyboard hotkey port switching works as expectedCons:Really Annoying: Monitor won't go to sleep, keeps trying to but then wakes up. I must unplug the KVM to get it to go to sleep.It took me a while to figure this out, but the Hotkey Setting Mode uses the '-' from the Num Pad and not the one from the keyboard.Minor: I get USB not recognized errors when switching to a different port the first time. Succeeding switches don't give me an error.