chromecast第二代，wifi support 802.11ac 5G，速度更快，效果應該更好。
Technical specification of Chromecast 2 :
The second-generation model uses a Marvell Armada 1500 Mini Plus 88DE3006 SoC, which has dual ARM Cortex-A7 processors running at 1.2 GHz. The unit contains an Avastar 88W8887, which has improved Wi-Fi performance and offers support for 802.11 ac and 5 GHz bands, while containing three adaptive antennae for better connections to home routers. The device contains 512 MB of Samsung DDR3L RAM and 256 MB of flash storage.