I picked up an Asus AC86U earlier this year, deciding it was time to upgrade from the N66U and after rejecting the Netgear R7800. Since then Itís been solid as a rock, no complaints.
However, I recently noticed, when all the various PCs and drives were off, a quite distinct high pitch whine from the back of the unit.
My suspicion and a little bit of investigation found it to be coil whine being emitted by the 5Ghz radio. I fiddled with some settings but didnít find anything that reduced it.
I can put up with it as itís Ďmaskedí most of the time and any RMA replacement would be a lucky dip. 5Ghz isnít essential where I live as the 2.4Ghz band isnít likely to get congested and I have to extend coverage anyway with a TP-Link mini router which is hard wired (doesnít make a peep on 5Ghz)
That said, Iím curious how prevalent electrical noise issues are with 5Ghz and whether it would in any way affect performance? Iíve found a handful of Ďwhineí reports related to routers. My experience has often heard it from power adaptors and the like, as well as Intel Core CPUs but not a router before.