[操作疑難] 2009iMAC想買隻AC USB Adapter, 有冇師兄用緊有好介紹?

ASUS AC-51 usb2.0 呢隻OK唔OK?
定係其實分別不大?

ASUS AC-56 usb3.0, 但我部iMAC仲係得usb2.0,
會唔會speed drop down得好多, 變成浪費左?

而家Router 用緊Netgear R7000, 本來想買返netgear....但好似冇OSX driver.....