So i have a rather curious conundrum. I've had a 2014 retina iMac for a little over a year now. For reasons unbeknownst to me, from day one the ethernet has been horrible on this machine. It cuts out every couple of minutes even though pings still go through, and Apple Support can't make heads or tails of the problem. I know it's not the cord, because I've tried swapping out cords. I know it's not the router, because I've tried plugging the exact same cord into my laptop and it works flawlessly. The problem is definitely the iMac. However, because the machine runs well otherwise and wifi works flawlessly, I have decided to just leave things as is for now. I do have AppleCare with the three-year warranty, so I suppose I can always get it taken in in the future if I change my mind. HOWEVER, I have recently run into a NEW conundrum. I have an incredibly narrow computer desk due to my workspace (okay, actually it's a card table ssshhh), which makes using dual monitors impossible. But I occasionally do need an extra monitor when I'm doing video work. So I purchased this portable USB 3.0 monitor, so that I can plug it in when I need it and tuck it away the rest of the time. The issue? It kills my wifi. Like to a crawl. And it's definitely the monitor. The wifi will be perfect, then I'll plug in the monitor and the wifi immediately cuts out and will not return until I unplug the monitor. Which is... vexing. Googling the issue brought me to this page by Apple which states "Certain external monitors and LCD displays: Certain displays can emit harmonic interference, especially in the 2.4GHz band between channels 11 and 14. This interference might be stronger if you're using a notebook computer with the lid closed and have an external monitor connected. Try changing your access point to use 5 GHz or a lower 2.4 GHz channel." Greeeeattttt. Well, unfortunately while my router broadcasts 5 GHz, it does not support broadcasting the 5 GHz network on a separate SSID, and due to distance from the router my iMac will only connect to the 2.4 GHz network. I tried every single channel on the 2.4 GHz network and it didn't help one iota. So my question is, did anyone else have this issue, and did switching to a 5 GHz network actually fix it? Because I have an ethernet cord just lying under my desk that runs directly up to the router, so I'm considering buying an Airport Express and plugging it into that cord to broadcast my own little 5 GHz network in the basement, but I'm not sure it would actually help or not. I just want to be able to use my external monitor and the wifi at the same time @-@ Also, does the Airport Extreme use a different 5 GHz signal than the Express? I'm wondering if I'd have more luck with one versus the other. I have no need to connect wirelessly to other devices in my house and we're only on a mid-tier DSL, so I didn't think the Extreme would actually give me any advantage speed-wise, but I'm wondering if it would have any advantage interference-wise. Because that's my real issue here.