So your passive HDMI adapter might be one that is limited to 1920x1200. Some mid-range DP -> HDMI adapters such as the Plugable MDPM-HDMIF are capable of operating at up to 300MHz, but ultimately they are still reliant upon the Dual-Mode functionality of the host to transmit the TMDS signal required for HDMI/DVI displays. This limited clock rate generally limits the maximum resolution to 1920×1200 and reduces the maximum available color-depth to preserve the limited bandwidth.

When outputting a TMDS (DVI/HDMI) signal through Dual-Mode, most DisplayPort sources as well as the inexpensive passive adapters on the market are limited to a 165MHz clock rate. There are active DisplayPort to dual-link DVI adapters available, and these require the use of a dual-link cable:įor HDMI, there are both active and passive adapters available which support HDMI 1.3+, however one vendor adapter (Plugable) claims: Passive DisplayPort to dual-link DVI adapters do not exist due to DisplayPort's limited number of pins. So if the DisplayPort input on the monitor isn't already occupied, the cheapest and/or least confusing solution might be to use a Mini DisplayPort to DisplayPort cable. The MacBook Air (Early 2014, both the 11-inch and 13-inch models) supports up to 2560x1600 over DisplayPort. That monitor has a native resolution of 2560x1440, which requires either DisplayPort, dual-link DVI, or HDMI 1.3+ (the monitor might still work with single-link DVI or HDMI 1.2− if the MacBook is set to output a resolution of 1920x1200 or lower): The asker's own answer clarifies that a BenQ BL2420PT monitor was what wouldn't work with the passive adapters.

Macbook air converter to hdmi