This is quite a difficult issue to explain, but this weekend I was using Plex to catch up on a few box sets of shows which I have been meaning to watch for a while, and I had some troubles with navigating between shows on my PS3.
When the app first loads it is nice and responsive, but after watching each show (~45 mins playback each) the interface seemed to get slower and slower each time. An example of this is after about the 3rd or 4th show as it ended playing the episode details screen took over 15 seconds to finish loading all of the info about that show (background image and video/audio quality logos seem to be the last things to load) and while waiting for this the interface was completely unresponsive. I think this is progressively slower with each episode I watched and my patience ran out after watching 4 shows each time.
To be clear this is not the playstation itself becoming slower; pressing the PS3 button responded immediately and I was able to close the Plex app. Reloading mean the app was responsive again.
This issue only seems to have appeared as of the latest (2.4.19) release.
For background, my PS3 is connected via WiFi to my network, my PMS is 0.9.12.11 running on Windows Server 2012 R2 on an HP MicroServer Gen8.
If you need any further details please let me know, but testing this further may need me to wait for the weekend when i have time to watch 4 episodes of a show back to back :)
Any advice or suggestions gratefully received.