DisplayPort 1.2
Direct Answer
DisplayPort 1.2, released January 7, 2010, doubled maximum bandwidth to 21.6 Gbps via a new High Bit Rate 2 (HBR2) mode, enabling 4K at 60Hz for the first time. Its headline feature, Multi-Stream Transport (MST), lets multiple monitors daisy-chain from a single DisplayPort output.
Source: VESA DisplayPort 1.2 Specification
Specs
| Release Date | January 7, 2010 |
| Max Bandwidth, HBR2 4 lanes (raw / effective) | 21.6 / 17.28 Gbps |
| Max Resolution | 3840x2160 (4K) @ 60Hz, 10-bit color |
| AUX Channel Bandwidth | up to 720 (up from 1.0's 1 Mbps) Mbps |
Multi-Stream Transport: One Port, Several Monitors
DisplayPort 1.2's headline feature, Multi-Stream Transport (MST), lets a single DisplayPort output carry multiple independent video streams at once -- each addressed as its own logical display -- so several monitors can be daisy-chained from one source port or fanned out through a hub/dock, rather than each monitor needing its own dedicated video output. This is the feature that made multi-monitor USB-C docks and daisy-chainable displays practical.
The new HBR2 link mode nearly doubled raw bandwidth to 21.6 Gbps, enough to finally support 4K (3840x2160) at 60Hz with 10-bit color -- a capability neither HDMI nor DisplayPort 1.0 had at the time. DisplayPort 1.2 also greatly increased AUX channel bandwidth (from 1 Mbps to 720 Mbps) for faster device communication, and added stereoscopic 3D video support.