And here I am laughing on my speedy private instance. For real, the best part of Lemmy is if your experience is bad you can hop to a different instance and not miss a post
Everything is faster. For the most part, your local instance will download posts and comments for any community you (or anyone else on your instance) is subscribed to. So when you log in, you log into your server and browse the content locally (posts from everywhere) while your server in the background constantly is receiving updates through the ActivityPub protocol.
I literally have no delay in using Lemmy in any way.
The "all" stream would be all of the posts from the combined subs of the users on the instance. So if there's a community nobody is subscribed to, it won't appear on all. This is true of all instances. Many smaller ones will employ bots to crawl Lemmy and sub to communities to give the large instance "all" feeling.
That being said, yeah it's all preloaded onto your local server. There is no difference in speed. Doesn't matter if it's active/subed or new/all they all load the same
I'd highly encourage everyone to find smaller instances and leave lemmy.world for the immediate expats. Find something that aligns with your values. Or if you are technically literate enough host your own instance. If you have an old desktop computer you've already got everything you need.
In just a week, With BTRFS compression (compress-force=zstd:3) & deduplication (via bees), media is at about 1GB (and I am subscribed to media-heavy communities like 196) and the postgres DB is at about 550MB (which is also currently shared with Matrix Dendrite)
At "idle" (as you can be while being connected to ActivityPub & Matrix), the immediate CPU and RAM usage breakdown per container is:
Net IO you shouldn't really care about as that includes inter-container networking. I'm trying to find how much outgoing data have been transferred but because the month just ended I have no idea how accurate the numbers are.
On my instance we've got about 100 communities subscribed to. Started it first week of June, since then the instance is up to a little over 4 GB of disk space. YMMV depending on instance size.