Foreign media found that 2015 MacBook Air is really able to achieve the laptop external 4K monitor.
At the time of release, Apple had said that a new generation of MacBook Air could support an 2560x1600 resolution of an external monitor, with no mention of 4K. But the latest test is that the 2015 MacBook Air can support the Dell p2415q 24-inch 4K display, and the refresh rate does reach 60Hz.
In the test, the MacBook air correctly recognizes the p2415q display and plunges the user interface into HIDPI mode.
Of course, although support 4K 60Hz refresh rate, but full screen 3D fluent performance is very poor, often the problem of dropping frames.
After looking further at Apple's developer documentation, the foreign media found that Apple labeled a new generation of MacBook Air does support 4K resolution, but recommended 24/30hz and did not mention 60Hz.
It's not surprising that the new MacBook Air supports 4K 60Hz, because Intel's HD 6000 core graphics card has made it clear that it will support such a resolution, and Apple's own Thunderbolt 2 interface bandwidth is sufficient.