Plex sync on my home network takes so long to sync just a few TV shows that everything times out and fails. If I keep my device "alive" it will eventually finish, but usually takes at least an hour for only 2-3 TV shows.
Streaming to Roku/Web player works just fine, so I know it's not a network speed issue. Streaming non-synced content to the same iOS device that is having sync issues works just fine (no buffering while at home). Syncing to an Android device is speedy fast, so that rules out the whole Sync feature being the problem.
My setup is an Apple Airport Extreme (newest generation), and Plex Media Server running on a Mac Mini. My media is stored on a Drobo, connected via Firewire to the Mac Mini.
Potentially related: when I have my Plex iOS app open and am attempting to sync content from the PMS, wireless networking speed for my other devices nearby drops to unusable - webpages take 5 minutes to load.
I don't remember this being such a prominent problem before iOS 8 (or my iPhone 6+), so maybe something changed in those APIs regarding syncing functionality that needs to be looked at?
All other functions on my iPhone 6+ work as they should, including running a speed test while on home Wifi and receiving incredible speed results.
I have only played around with sync on my iPad or iPhone a couple of times but it's been so slow every time I have tried that I just give up. This has been going on with several different iPad and iPhone versions and many, many versions of iOS.
I have seen some of those other threads and essentially consider sync a worthless feature.
I I have a suspicion about what might be causing your problem, though I'm not sure if it applies to your situation.
The fact that the *transfer* is slow (as opposed to transcoding) points to a problematic router configuration. You've indicated that during sync, your other devices slow down as well. This sounds like your router is throttling data transfer, which possibly could be due to Quality-of-Service (QoS). While QoS reshapes network traffic to ensure minimum external bandwith (ie, WAN) to individual protocols, it's generally not enabled to reshape traffic within the network (ie, LAN). If I set QoS on my DD-WRT based router to just WAN, data transfer speeds within the local network are unaffected. If I set it to cover both WAN & LAN, even Plex streaming slows to a crawl (if the Plex streaming bit rate is lower than the QoS uplink speeds, you may not notice a difference).
This to me sounds a lot like the problem you describe, though I have no clue if this is indeed the case for you as well. I have no idea if your router (Airport Extreme) supports QoS, but it sounds like it's doing something effectively similar.
Local streaming requires much less bandwidth (~3Mb/s), which could explain why Roku and Web client streaming works for you. That same data transfer rate would be intolerably slow for file transfer.
Thanks for your reply, it's not a QoS issue. Apple routers don't support this (at least not with a public option), and devices away from my phone (while being synced) work fine...just devices very close to the phone - within 5 feet or so - tend to slow down. I think this is more related to the intensity of the data transfer and the wavelengths involved with WiFi than part of the problem of Plex Sync on iOS.
I I have a suspicion about what might be causing your problem, though I'm not sure if it applies to your situation.
The fact that the *transfer* is slow (as opposed to transcoding) points to a problematic router configuration. You've indicated that during sync, your other devices slow down as well. This sounds like your router is throttling data transfer, which possibly could be due to Quality-of-Service (QoS). While QoS reshapes network traffic to ensure minimum external bandwith (ie, WAN) to individual protocols, it's generally not enabled to reshape traffic within the network (ie, LAN). If I set QoS on my DD-WRT based router to just WAN, data transfer speeds within the local network are unaffected. If I set it to cover both WAN & LAN, even Plex streaming slows to a crawl (if the Plex streaming bit rate is lower than the QoS uplink speeds, you may not notice a difference).
This to me sounds a lot like the problem you describe, though I have no clue if this is indeed the case for you as well. I have no idea if your router (Airport Extreme) supports QoS, but it sounds like it's doing something effectively similar.
Local streaming requires much less bandwidth (~3Mb/s), which could explain why Roku and Web client streaming works for you. That same data transfer rate would be intolerably slow for file transfer.
I have found that if your Plex server is streaming to another device while it is trying to download to your iOS device, then you can see high CPU usage and a reduction in your synch speed.
