StarTech.com 4 Port DisplayPort KVM Switch w/ Audio - USB, Keyboard, Video, Mouse, Computer Switch Box for 2560x1600 DP Monitor (SV431DPUA) - KVM / audio / USB switch - 4 ports

Share keyboard, mouse, and DisplayPort display between four HD multimedia systems. The SV431DPUA 4 Port USB DisplayPort KVM Switch with Audio combines next generation display standards with seamless KVM control of up to 4 connected PC or Mac computers.
Featuring DisplayPort resolutions of 2560x1600 @60Hz, as well as offering both 7.1 HD digital audio (with supporting displays and sources) and separate 3.5mm stereo audio support. An integrated USB 2.0 hub allows you to share 2 additional peripherals among attached computers as if they were directly connected.
Suitable for high quality static imaging applications such as health care (MRI, X-ray diagnostics, etc.), a maximum resolution of 3840x2400 is supported at reduced refresh rates.
A simple yet comprehensive solution, the 4-port KVM features both front-panel push-button and hotkey switching, and offers a small form factor with rear connection ports, to minimize workspace disruptions.
If you'd like to mount this KVM switch to your server rack, StarTech.com offers a 1U Rackmount Bracket (sold separately) that turns this KVM into a rackmountable KVM.