BYOND Version:494
Operating System:Windows 7 Ultimate
Web Browser:Chrome 18.0.1025.162
Applies to:Dream Seeker
Status: Unverified

Thus far we've been unable to verify or reproduce this bug. Or, it has been observed but it cannot be triggered with a reliable test case. You can help us out by editing your report or adding a comment with more information.
I honestly have no idea what this is, but ever since I updated my BYOND version to the latest version of the beta clients who are playing on servers that aren't local seem to have to download resources every time a new icon is processed

This might have something to do with fcopy_rsc(). While the icons are downloading(Why would the client have to download more icons if the icon processing is on their end?) the clients freeze up until the download is complete. This makes Epic unplayable when hosted online

Another strange thing about this is that if you are playing locally there is no speed loss/random downloads. If I host the game and join it, I can play it without any speed issues. But if someone else hosts it and I join their server, I have to download more resources with every single new icon.

I'm not sure if this is a new problem or if we somehow just didn't have it before because of the old .rsc we had, but it is definitely problematic and sudden and negatively affects how many people play the game
It's important to narrow this down, so I strongly advise you to try hosting this in earlier builds, and also playing in earlier builds and see if that makes a difference. It'd be useful also to know if combinations like hosting in 493 and joining in 494 make a difference.

There was a leak fixed regarding client-side icon processing but I doubt this is an issue in any way. Beyond that, I can't think of any changes to icon processing that'd be relevant in any way.

Also, if I'm to investigate this myself then I'll need a test case. I'll need to know which games this is happening in (hub links please), and what steps to follow to see the issue in action. For lack of a test case or more information, I'm moving this to Unverified for now.
Lummox JR changed status to 'Unverified'
I was wrong about this, but I'm almost certain now that this is caused by clients importing and exporting savefiles.

The big problem is that when a savefile is sent to just one client or loaded the entire world bogs down for a moment until it is finished
I believe I know a reason for this. If you're using Garthor's safe save library, that includes the original savefile as a cache file object in a "wrapper" save that is actually sent to the client. As a result of the savefile being stored this way, it becomes a resource that clients think they need.
nope, we're just using client.Import() and Export() and writing stuff to the savefiles. The heftiest stuff we're saving is just a list of items, and creating those in the game does not cause any CPU issues. Besides a list of items, it's mostly just binary values and some strings
Can you verify with ExportText() that there are no cache files being included in the save? Saving an icon file might be enough to trigger this issue if it's not the default icon and you'd have to override Write() to prevent that. The same applies for overlays.