There are already plenty of tools that let you record 1080p video of your games and other activities. Need higher resolution video for your work? These 3 4K video grabbers can help:
AV.io 4K videp capture: a rugged and portable video grabber for Windows, Linux, and Mac OSX. It has DVI-D and HDMI inputs for video up to UHD 4K at 30 fps. It is compatible with various video encoder software.
Magewell Pro Capture HDMI 4K Plus: this capture card records ultra HD 60fps video. It is compatible with Windows with Linux support in the works.
Blackmagic Intensity Pro 4K Capture Card: lets you record Ultra HD at up to 30 fps. It has HDMI input/output for video and 8-channel audio. Useful for capturing games and streaming.
Have you found better 4K video capture cards? Please share them here.