DisplayPort Alt Mode 2.0 is a new standard from the Video Electronics Standards Association that allows USB 4 to offer all the bells and whistles of the DisplayPort 2.0 standard as well as transmitting USB data. That means support for 8K displays at 60Hz with HDR, 4K displays at 144Hz with HDR, or even 16K (15360x8460) displays at 60Hz with compression. It’s a big step towards USB Type-C becoming a true jack-of-all trades connector.
The USB 4 spec can already transmit DisplayPort data, but AnandTech reports that the new standard remaps USB-C’s high speed data pins to unlock more bandwidth for video. USB 4 is bidirectional, meaning it can carry up to 40Gbps of data in either direction. However, video doesn’t need to go both ways — you only really need data to pass from your laptop to your monitor (for example). This alt mode means that all that bandwidth can be used to just send video one way, meaning you get a maximum raw bandwidth of up to 80Gbps.
Up to 80Gbps of video bandwidth over USB-C
The alt mode also has other advantages. For example, it means that you don’t need to have a USB 4 controller at either end of the cable, you can get away with just DisplayPort hardware at the display end. This should mean displays can afford to be slightly simpler, according to AnandTech.
This is a very simplified account of VESA’s Alt Mode 2.0 announcement, and we’d thoroughly recommend heading over to AnandTech if you’re after a deeper dive into the details of the spec. VESA says that it expects the first DisplayPort Alt Mode 2.0 devices to start releasing next year. As is always the case with USB, however, you’ll have to pay close attention to certifications and the small print of your devices and cables to make sure they support all the new features.