Ars Technica reports the recently refreshed Intel Broadwell-equipped MacBook Air can support 4K external displays at a 60Hz refresh rate. Previous generation notebooks based on Intel’s Haswell platform were limited to lower resolutions.
While Ars Technica reports the 4K support is there, Apple’s tech specs page for the new MacBook Air lists the new notebook as capable of supporting an external display of up to 2,560×1,600 pixels via an Intel HD Graphics 6000. Apple may be reluctant to promote the 4K support, due to somewhat laggy performance in some cases.
“Dropped frames are clearly visible when entering into Full Screen mode or using Mission Control, and of course you’ll never want to try playing games or doing heavy 3D work at native resolution. But things are more than smooth enough for desktop use.”
The report says scaling the display up definitely puts a hit on performance, noting if you take a larger 4608×2592, 5120×2880, or 6016×3384 image and scale it down to fit the 3840×2160 resolution of the display, animations become jerky, transitions become “flip books,” and even scrolling takes a small performance hit around the 5120×2880 level.
The new MacBook Air’s Thunderbolt 2 port is compatible with the DisplayPort 1.2 specification, with 4K support over HDMI limited to a 24Hz refresh rate.