I experienced a weird performance issue on an Acer laptop when connecting to a PC acting as a server in LAN multiplayer, despite the same laptop being able to run older multiplayer on 0.15 versions of Factorio as client. Singleplayer performance is fine for the laptop though.
First off catching up usually fails, the progress bar shrinks constantly instead of growing, unless the server pauses the game until the laptop can finish catching up. After connecting the FPS are a greatly reduced on the laptop (usually below 5 FPS), while the server is fine and experiencing no issues. For the laptop Factorio is unplayable at that point, and no combination graphical options selected (size of sprite atlas size, texture compression on/off, smoke on/off etc) can influence performance noticeably. Meanwhile the core handling Factorio runs at max load as is observable from the OS' process explorer on the laptop. This weird load spiking occurs both on saved games with medium sized bases as well as new games with no base at all.
There is no problem when the laptop is the server though: Performance for the laptop as a server is fine, as is for the connecting PC. Load on the core running Factorio is evidently way lower (17% instead of the max 43%; laptop is a triple core hence the odd numbers here).
But as I said performance on the laptop wasn't always an issue. I happened to have a zip with 0.15.3 saved and when investigating both cases (laptop->server&PC->client and vice versa) there seems to be no problem at all. It must have been a change to Factorio in one of the recent versions, probably in 0.15.20 or later (was no problem a few weeks ago) and persists on the recent 0.15.26 version.
If someone can provide me with zips of older versions I gladly do my part to narrow it down more in order to make resolving this annoyance as easy as possible for you
.Best regards
DerSpini
