i have 2 macs in my lounge. my 2011 imac is mine, but my old 2009 mac mini runs all of our tv stuff, not only streaming tv but also i use plex for downloaded films and tv, which it streams to our samsung tv which has a plex app. i do the downloading on my iMac, then copy files across to the mini by wifi. it takes seconds as you'd expect, for an episode of tv. I've been working the same way for months. suddenly last night, downloaded blacklist and nashville, went to copy them onto mini, its taking 2 hours for one episode to copy. I've reset both machines. I've reset the router. I've tried different files. I've copied the files onto my iMac internal drive before copying to the iMac in case its the external drive i download onto. it can't be anything to do with the mini's wifi or external drive as its still streaming merrily to the plex app on the tv. normally it'll copy fine even when streaming something else, but in this case neither machine is doing anything except me typing this, and its taken about 5 minutes to copy 63mb.