I had been on the search for a KVM for my two dual-monitor systems for several months. I have a Mac Mini (with HDMI -> DVI and MiniDisplay -> DVI converter dongles) and a Dell E6520 laptop in a dock (with two DVI outputs). The Mac, of course, has never given me any display problems, but the E6520 running Windows 7 has some super finicky display drivers that have given me constant headaches (especially considering I am using two Dell WFP2408 monitors). I mention this because if you have ever used a KVM before, you are probably aware that the KVM unit itself can introduce display detection problems and send display drivers into a tizzy.

This KVM worked flawlessly. Setup was a snap - pretty much just hooked up my cables and was good to go. The Apple worked right away, while the Dell did require a driver update to get it to work with the second monitor. I do not fault the KVM for this, as the dual monitor detection problems were exactly the same as when I originally setup dual monitors directly plugged in, so I had to go through the setup process again and "nudge" my Windows machine to see them both. After that, everything worked great.

https://www.amazon.com/gp/customer-reviews/R4F3ZGAW0XYTF/ref=cm_cr_getr_d_rvw_ttl?ie=UTF8&ASIN=B004GKM9JK

I had a fairly complex set up need: sharing peripherals (dual monitors, keyboard, and mouse) between a Windows desktop and a late model MacBook Pro with USB-C ports only. I couldn't find anything off-the-shelf to make this configuration work, so here's what I came up with.

I got a small dock for the MBP that could take the standard USB port (allowing shared keyboard and mouse) plus dual monitors. Unfortunately, I could not find *any* MBP docks that use DVI (needed for this switch), so I bought a few other adapters (hdmi to DVI, Mini display port to DVI) and made the connections between the hub and the switch that way. The switch-to-desktop setup didn't need any of that since my graphics card has DVI ports.

Still -- running this setup through adapaters, a MPB hub, and a switch -- the thing just works! Out of the box. Didn't even have to crack the instruction manual (but was ready too!)

Now my spouse and I can share a desk during the COVID lockdown - how romantic.

I was a little worried about buying this dual monitor KVM; it's a little pricey IMHO. But I really wanted to have a dual monitory setup, and I have two PCs and I didn't want to have to set up 4 monitors, nor did I want to have to move cables between them.

I've been using this for about a month, and so far so good. Let me explain that primarily I don't operate both PCs at the same time - I usually only have one powered up at a time, so I don't do too much hot switching. I have done it with this GCS1642 just to experiment, and it worked just fine, but I don't do a lot of this. Instead, I am using the KVM to save space mainly, so I select the active PC prior to boot, then leave it alone for the duration of my working session. I have not yet experienced any signal loss, except I noticed a bit of wonkiness when I first removed from my (separate) connected USB hub (see below). Not a big deal, and I wouldn't say it was causing a problem.

The cables work well and cut down on cord mess because they're a single cord with multiple connections, and they carry both monitors, the Keyboard, Mouse and USB from the KVM to each attached computer. I have USB speakers and headphones, so I didn't use the audio connections at all, thus I can't speak to whether they work or not. I attached a 10-port USB hub to the USB-in on the KVM, and I haven't had any problems with multiple USB devices being shared on the hub (I usually have speakers, headphones and a couple of external hard drives attached).

My recommendations:
- Get the HDMI variant if you're unsure. I got the DVI (and that's the one I've used and am reviewing) because it matched my existing monitors, but I think that was a mistake. Most of the monitors I see for sale at Best Buy, etc have HDMI connections, but very few have DVI in.
- Attach a USB hub to the USB in, and depending on your setup, get a long cable so the hub isn't in the way. They put the USB port on the front for some reason, so if you have this KVM front and center in your setup like I do, any device attached to the USB port gets in the way.

Things I don't like
- I wish it had a separate power button. You can unplug it, or put it on a switched power supply, but it doesn't have its own power button.
- I don't like the USB port in the front - it would work better for me if it was on the back like every other port. Also, it's a USB 2.0 connection (that doesn't hurt me, but FYI)
- (very minor) The unit selection buttons are a little hard to press positively. I'll probably get the hang of them, but I tend to double press them due to their form.
- (very minor) The power adapter plug doesn't seat all the way into the DC in (lower left on the picture of the rear of the unit. This seems to have been a hack because of the lip of the case interfering with the seating of the DC power in. This doesn't cause a functional problem that I can tell, but it leaves a bit of the plug exposed (that can't be good) and it just seems a little junky.

Can't speak to:
- The speaker/mic connection
- I never change the sharing mode. Apparently you can select whether or not to share the audio and monitor connections. I never change this, and always share everything.

Overall: Doing what I want it to do with no signal loss, no device hiccups I've seen so far, no problems setting it up, and no real functional issues I've encountered. Bit pricey, and I'd like to see an updated model, but otherwise working well.

I bought this to switch my monitor between two systems (Linux and Windows) mainly for gaming use. This required that I would have no input lag and the ability to disable emulation.

Multiple reviews indicated that I might not have been able to do that: disable emulation, so that I could use my gaming mouse and atypical keyboard.

They're all wrong.

In the user manual (oh, people don't read these? I DO!) on page 22... Hotkey Setting Mode... it says to invoke Hotkey Setting Mode by holding Num-Lock and pressing the Minus (-) key before releasing Num-Lock.

When in HSM, then press "m" to disable Mouse Emulation.

Do the Num-lock minus thing again,

Press "n" to disable Keyboard Emulation.

Now you have a dumb switch that will pass through everything. You can now use any keyboard and mouse you want and it will work.

I'm using a Lepopold FC660M keyboard and Logitech G5 Mouse with this switch and everything works great. There's some re-detection delay of mouse and keyboard when I switch which machine it's linking me to, but that's over in a second and I'm back to playing games on my second machine.

Oh, and since nobody reads manuals but likely reads reviews... Scrl-Lock, Scrl-Lock, Enter is how you switch inputs without pressing the buttons the switcher itself. There's a number of other keyboard shortcuts you can learn to be able to fully remotely control your switch without having to have access to it.

These are some really powerful features on this switcher. Read the manual. You'll be impressed with what you can do.

Can also confirm that the model I bought supports dual-link DVI monitors.

PROS:

+ Cables included
+ Small size
+ Front buttons and LED indicators are easy to use and understand
+ Works well with ultra-high resolution monitors (2560x1440)
+ Manual is clear and makes use easy
+ Hot keys can be re-assigned
+ Beep can be disabled (unfortunately my PC still beeps when it detects the USB connections changing... oh well)

CONS:

- Sometimes when switching, the keyboard repeats key presses like "jjjjjjjjjjjjjj". This typically only happens within the first 3 seconds of switching ports. This also happens repeatedly if one PC is turned off. This does NOT happen if you plug the KVM cables into a set of always-on USB 2.0 ports on your motherboard (on my Asus mobo the 3.0 ports are not always on).

SOLUTION: Wait a few seconds before you start typing, and be sure both PC's are turned on.

- Sometimes after switching, the keyboard and/or mouse is not recognized by the active PC.

SOLUTION: I discovered that moving the KVM USB cable to a different USB port on your computer can solve this problem. In my case, I moved the KVM USB cable to a USB 2.0 (not 3.0) pair (not quad set) of ports which fixed this issue on a newer Asus motherboard. The trick here is to discover what USB ports are "always powered" on your motherboard at startup. This can easily be done by plugging in an optical mouse and looking at the mouse's laser light during startup. If the light is off, use a different USB port. I can only assume the USB 3.0 ports I tried using have some sort of software emulation which caused problems (hence the need to install a software driver before they would work at all).

In the end I am using a HP Wireless Elite Keyboard v2 and mouse. The keyboard is plugged into the "keyboard" USB port, and the mouse receiver is plugged into the front USB port.

Everything works fine this way.

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[UPDATE] I purchased an HP Wireless Elite Keyboard v2 and plugged it into the keyboard port and it works fine - it will toggle the KVM using the hotkeys. No additional setup was needed. However, the special "function" buttons like mute, volume, etc., still don't work (but I never use them anyway, so I don't care).

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LOGITECH INSTRUCTIONS:

I *was* using the Logitech Wireless Combo Mk520 With Keyboard and Laser Mouse (920-002553) and had a very frustrating time getting this to work. In the end, I discovered the wireless keyboard will work, but you can NOT use it to switch the displays using the hot-key sequences. You MUST use a wired (or non-Logitech) keyboard to use the hot-key controls.

DIRECTIONS:

1. Turn off the power to everything, INCLUDING your monitors and the KVM.

2. Plug the Logitech wireless receiver into the REAR third USB port located by itself (for using the Logitech keyboard AND mouse) or the front USB port (for using a Logitech mouse ONLY)

3. Turn on your power to everything (KVM should be powered on here), turn on the monitors, then turn on your first computer.

4. If they keyboard and/or mouse do not work (as did mine) turn OFF the power to the mouse (the Logitech has a switch, you may have to remove the batteries) wait 5 seconds, then turn the mouse back on. In my case this made them start to work. Apparently this is how you enable the Logitech "Unifying" link system.

6. Now press the "Next PC" button (2) on the KVM box. Repeat step 4 if needed (I had to do this).

Now both computers should see the mouse.

HOWEVER, IoGear confirmed that the Logitech "Unifying" receiver will NOT operate the hot keys via their wireless keyboards, so if you use a Logitech keyboard you must press the button on the KVM to switch between machines.

Also, any "special" function buttons won't work, like volume, track next/prev, sleep, etc.

FINAL NOTE: IoGear's website says:

In order for hot key operation and instantaneous keyboard and mouse recognition when switching computers, our KVMs emulate a standard wired 102 key keyboard and wired generic 2-button scroll wheel mouse on their respective console ports. Although the KVM will function correctly with most wireless sets, because of the single input to the KVM, we cannot guarantee a particular wireless set will function with the KVM. If a wireless combo is going to work the single USB receiver would need to be plugged into the keyboard port of the KVM. However the KVM does two USB peripheral sharing ports which a wireless keyboard and mouse combo can be used through. If one of these ports is used for the wireless combo then all port switching will have to be done manually using the port selection buttons on the front of the KVM.