What is single-link DVI?
Single-link is a DVI configuration that uses one TMDS link (transition-minimized differential signaling): three data channels plus a clock, carrying digital video from the graphics card to the monitor. A single link tops out at a 165 MHz pixel clock, which is enough for about 1920x1200 at 60 Hz, and so for 1920x1080 at 60 Hz. Anything beyond that, such as 2560x1600 at 60 Hz or 1920x1080 at 120 or 144 Hz, needs dual-link DVI.
Single-link and dual-link apply to the digital DVI variants, DVI-D and DVI-I. DVI-A carries only analog video, so the idea doesn't apply to it.
How to recognize it
A DVI connector has a grid of up to 24 pins in three rows of eight, plus a flat blade on one side. A single-link connector is missing the six pins in the middle of the grid, which a dual-link connector uses for its second link.
| Connector | Pins |
|---|---|
| DVI-D single-link | 18 + 1 (the blade) |
| DVI-D dual-link | 24 + 1 |
| DVI-I single-link | 18 + 5 (the blade plus four analog pins) |
| DVI-I dual-link | 24 + 5 |
Mixing single-link and dual-link
- A dual-link cable works fine for a single-link connection; the extra pins just go unused.
- A single-link cable or port on a high-resolution monitor limits it to single-link bandwidth, so the monitor may run at a lower resolution or refresh rate, or show no picture at its native settings.
- A passive DVI-to-HDMI adapter carries a single link.
Video only
DVI carries video, not audio. When a DVI-connected monitor or TV has no sound, the fix is a separate audio connection or a switch to HDMI or DisplayPort, not a different DVI cable.
For the CompTIA A+ exam
Core 1 (220-1201) objective 3.2 lists DVI among video cables. Single-link and dual-link aren't named, but a monitor that won't reach its full resolution over DVI is a classic link problem: check that the graphics card, cable and monitor are all dual-link before blaming the driver.