I am a huge fan of Plex and use it a lot. We have a ton of our movies on my notebook where my plex server software runs and I typically am casting it to one of our TVs connected via a Chromecast 2.
As I was looking at laptop options and moving a lot of data potentiall to an external HDD, it occurred to me that I don't really understand how Plex "works" when streaming it to, say, my Chromecast. I know I have a media folder on my laptop, that the Plex software somehow sends it to the Chromecast. But I'm not entirely sure of the mechanism. Is it using the wireless connection of my laptop to upload the media file I'm casting to the Chromecast? In which case, speed of access to the file (i.e. where the file is on an SSD on my laptop or an external HDD) doesn't matter? Or does it? I assume the upload speed of my internet provider is the bottleneck when casting from the Plex media on my laptop to the Chromecast? Vs. my D/L internet speeds?
And somehow when I use the Plex app on my iphone, is it simply sending commands to my laptop and the Plex software on there?