Resolution and refresh rate are one figure, and the switching method is the other
A KVM switch lets one screen, one keyboard and one mouse drive several computers, and the specification that decides everything is the video path. Every model publishes a maximum resolution and refresh rate together, and the pairing matters: a switch quoted at a high resolution only at a low refresh rate is a different object from one quoted at both. It also names the socket it carries — DisplayPort, USB-C, or an HDMI output on many models. That figure is a ceiling for the switch alone; the computers and the screen each impose their own. Count the ports, which is to say how many computers it accepts, and the number of screens per computer, since dual-screen models exist and cost accordingly. The switching method is the second decision: a button on the front, a wired remote on the desk, a keyboard shortcut, or an arrangement that follows the pointer from one machine to the next and carries the clipboard with it. Peripherals come next. USB sockets on the switch are shared between the computers and some are reserved for keyboard and mouse; models stating a USB 3.x generation on the shared sockets are the ones that will carry a fast drive between machines. Audio is often a separate pair of jacks that switch with the video, or is not switched at all. Finally, read what is in the box, because a switch without the right leads is a switch plus a shopping list. We compare port count, maximum resolution and refresh rate, video connector type, screens per computer, USB port count and generation, switching method, audio support and cables supplied.
four computers · one VGA screen · 1920 by 1080 · push button only · a hub of uncounted sockets · no refresh rate printed
A four-computer VGA switch worked by a button on the front, whose resolution is printed in a form that leaves no room for a refresh rate.
Best for: A workshop or a back office keeping several older machines on one VGA screen, where a button on the front is the whole interface that is wanted.
≈ £19 / 15 €
four computers · one VGA screen · 1920 by 1440 · three USB 2.0 sockets · button or wired controller · four combined leads supplied
A four-computer VGA switch supplied with four combined leads and a desk controller, quoting a resolution above the usual 1080p ceiling and no refresh rate at all.
Best for: A desk running three or four machines on one screen where the switching should happen from the hand rather than from the unit, and where the keyboard is a plain one.
≈ $34 / £25 / 34 €
four computers · one screen · 8K at 60 Hz and 4K at 144 Hz · HDMI 2.1 · four USB 3.0 at 5 Gbps · panel button or wired controller · four USB leads and an adapter supplied
A four-computer HDMI switch that publishes two resolution and rate pairs, supplies its USB leads and a power adapter, and says outright that the final figure depends on the machines.
Best for: A desk of four machines on one screen where fast peripherals move between them, and where the window arrangement has to survive every change of machine.
≈ 73 €
four computers · one screen · 4K at 60 Hz and 2K at 100 Hz · one DisplayPort, one USB-C and two HDMI inputs · four USB 3.0 at 5 Gbps · button or wired remote
A four-computer switch whose inputs are of three different kinds, quoting its resolutions and refresh rates as pairs and never listing what is in the box.
Best for: A desk where the four machines do not share a video socket between them, and where a drive has to follow whichever one is in use.
≈ 70 €
four computers · two HDMI screens each · 4K at 60 Hz · four USB 3.0 at 5 Gbit/s · buttons, wired remote or RS232 · four USB leads supplied
A four-computer HDMI switch carrying two screens for each machine, switchable three ways including over a serial line, whose packing list opens with a different maker name.
Best for: A control desk or a small studio running four machines across two screens, where a serial line is already available to switch them.
≈ 106 €
two computers · two DisplayPort screens each · 8K at 60 Hz · DisplayPort 1.4, no HDMI socket · four USB 3.0 at 5 Gbps · button or desk controller
A two-computer switch that carries two DisplayPort screens for each machine, states plainly that it has no HDMI socket, and names the machines it will not drive in pairs.
Best for: A two-machine desk with two DisplayPort screens, where the peripherals should follow whichever machine is in use and the picture never passes through an HDMI socket.
≈ $90 / £70 / 63 €
four computers · one VGA screen · 1080p · three USB 2.0 sockets at 480 Mbps · one button with an indicator · two combined leads stated
A four-computer VGA switch with three USB 2.0 sockets and a single button, whose fourth bullet describes two computers and a different eight-port model.
Best for: A desk with three or four older machines on one VGA screen, where a printer and a flash drive should follow whichever machine is in use.
≈ £18 / 30 €
four computers · one screen · 8K at 60 Hz and 4K at 120 Hz · HDMI 2.1 · hotkey, infrared remote or button · four USB 3.0 leads supplied · bandwidth stated two ways
A four-computer HDMI switch offering three ways to change machine, including a keyboard shortcut, whose own page gives its bandwidth and content protection two different values.
Best for: A four-machine desk where switching should happen from the keyboard, and where the buyer is willing to confirm the bandwidth figure with the seller first.
≈ 110 €
Every price named in a summary was read on the date that review carries. What a shop asks today is shown beside the product, and it moves.
