My router is a Netgear R6300 (v1) AC1750 with firmware V1.0.2.38_1.0.33 (I have not upgraded the router firmware due to known issues) Channel selection options for 5Ghz are 36,40,44,48, 143, 153, 157, 161.
I have no problems using my X with it (I left the router on the default channel 153 for 5Ghz)
While my iPad Air, iPad Mini w/Retina, iPad 3, iPhone 5s, Note 3, Note 2, Thinkpad with Edimax EW-7811Un b/g/n adapter, Samsung Ativ SmartPC Pro 700 (built in B/G/N), and even my two old Moto Xooms work on 5Ghz, my Galaxy S5 can't see the SSID for 5Ghz on the router unless I use channel 48 or below. But I don't care, my S5 is my work device and I rarely use it on wifi at home, so when I do, 2.4ghz is fine.