Computers Supported
How many computers can share the same monitors, keyboard and mouse.
When it matters: Count what you have now plus one if you add a laptop later. Each extra port adds size and cable clutter.
KVM switch specs explained
A KVM switch is a railway junction. Several computers are the trains, and your monitors, keyboard and mouse are the one station they share. The video specs describe how wide the tracks are: resolution, refresh rate and how many screens each computer gets. The USB specs say how busy the station can be. Emulation features keep each train believing it is still docked while you are away. Size the tracks for your fastest monitor, then check how switching works.
Basics
Displays Per Computer
How many monitors each computer can use through the switch at once.
When it matters: A dual monitor KVM needs two video cables from every computer. Trap: a laptop with one video output cannot fill two monitors without a dock or MST.
Video Path Type
How video is routed: single head (one monitor), independent heads (several monitors switched together) or KVM over IP (control across a network).
When it matters: Desk KVMs switch local screens with no lag. KVM over IP compresses video to reach servers remotely and is not meant for gaming or detailed visual work.
Video
Video Connector
The type and version of video port: HDMI 2.0 or 2.1, DisplayPort 1.2, 1.4 or 2.1, or USB-C.
When it matters: The version sets the ceiling for resolution and refresh. Your computers and monitors need matching ports, or adapters that can cut features like high refresh or HDR.
Max Resolution and Refresh
The highest resolution and refresh rate the switch passes to one monitor.
When it matters: Check the refresh at your monitor's resolution, not just the top resolution. Many switches pass 4K at 60 Hz only, which wastes a 144 Hz monitor.
All Displays Active
The resolution and refresh rate the switch can hold when every monitor is in use at once.
When it matters: Some switches hit their headline spec only with one monitor connected. This line tells you what a full multi-monitor desk gets.
Skip it if: Skip it for single monitor switches.
DisplayPort Link Rate
The raw speed of each DisplayPort connection, named HBR2, HBR3 or UHBR (the DisplayPort 2.1 rates).
When it matters: HBR3 carries 4K at 120 Hz. Higher 4K refresh needs DSC or a UHBR link. A version number alone can hide a slower link.
Skip it if: Skip it for HDMI-only switches.
DSC Support
DSC (Display Stream Compression) squeezes video so high resolutions and refresh rates fit through a slower link, with no visible loss.
When it matters: If the top mode needs DSC, your graphics card and monitor must both support it too, or you drop to a lower refresh rate.
Skip it if you run 4K at 60 Hz or lower.
MST Support
MST (Multi-Stream Transport) lets one DisplayPort cable feed several monitors.
When it matters: Lets a single cable laptop drive two screens through the switch. Trap: macOS does not support MST extended displays, so Macs mirror instead.
Skip it if every computer has one video output per monitor.
HDCP Version
HDCP (High-bandwidth Digital Content Protection) is copy protection that streaming apps and discs require.
When it matters: If the switch does not support the version your content needs, 4K streaming may drop to lower resolution or show a black screen.
Skip it if you do not watch protected video through the switch.
HDR and VRR Passthrough
Whether HDR (high dynamic range) video and VRR (variable refresh rate, such as G-Sync or FreeSync) pass through the switch.
When it matters: Games and movies lose HDR or tear more if the switch blocks them. Check both if you game through the KVM.
Skip it if: Skip it for office-only setups.
Switching behavior
EDID Emulation
EDID emulation keeps each computer seeing the monitor as connected, even while switched away.
When it matters: Without it, windows jump around and resolution resets every time you switch. Learn and lock copies your real monitor's details. It is one of the most useful features on any KVM.
Switching Methods
How you change computers: a front button, a keyboard hotkey, a wired remote, or moving the mouse past the screen edge.
When it matters: A wired remote helps when the switch hides under the desk. Hotkeys may fail with gaming keyboards on non-emulated ports.
Serial Or Network Control
Lets software or a control system switch computers over RS-232 or a network connection.
When it matters: Useful for automation, control rooms and meeting rooms.
Skip it if: Skip it for a home or office desk.
USB
USB Switching Speed
The USB speed of ports that switch between computers, such as USB 2.0 or USB 3.x at 5 or 10 Gbps.
When it matters: USB 2.0 is fine for keyboards, mice and printers. Webcams and external drives need USB 3.x ports to run at full speed.
HID Emulation
HID (human interface device) emulation keeps a virtual keyboard and mouse connected to every computer, so switching is instant.
When it matters: Faster switching and working hotkeys. Trap: emulated ports can break extra keys, software and high polling on gaming mice and keyboards. Use a plain USB port for those.
USB Shares Video Bandwidth
Whether USB data and video run over the same connection, as with USB-C, and so compete for bandwidth.
When it matters: On USB-C, a high resolution display can leave only USB 2.0 speed for data. Expect slower drives and webcams at top video settings.
Skip it if all computers connect by separate video and USB cables.
Power
USB-C and Power Delivery
USB-C host ports carry video, data and laptop charging on one cable. The wattage is how much charging power they supply.
When it matters: A laptop needs close to its charger's wattage to charge at full speed under load. A shared budget means two laptops split the total.
Skip it if: Skip it for desktop-only setups.
Audio
Audio
Audio jacks that switch speakers and mics with the computers, and whether sound can be pulled from HDMI to a separate output.
When it matters: Handy if your speakers are not USB. Without audio switching, sound stays on the last computer's output.
Skip it if you use USB audio devices through the switched ports.
Build
External Power Required
Whether the switch needs its own power adapter.
When it matters: USB-powered switches can reset when a computer sleeps. Externally powered units stay stable with more devices attached.
Skip it if: Skip it for simple two-computer switches with only a keyboard and mouse.
Rack Mountable
Whether the switch fits a standard server rack, and what the case is made of.
When it matters: Rack mounting matters in server rooms. Metal cases handle heat and knocks better than plastic.
Skip it if: Skip rack mounting for desk use.
Included Cables
How many video and USB cables come in the box.
When it matters: A multi-monitor KVM needs several cables per computer. Missing cables add cost, and cheap cables can limit high refresh modes.