We’re working on a game with a team, and most of the people playing our game have low-budget systems, so we try to optimize our games a lot. As builders, we optimize 3D objects as much as we can, put the meshes in “performance” mode, and turn off the CanCollide setting of all parts where it would be unnecessary to have “CanCollide” turned on, but some players still experience fps problems. In addition, players experiencing fps problems generally do not experience any fps problems when they are alone on the server. That’s why I thought the problem would be software problems, not 3D objects. What is your opinion?
Well, it could be of many unknown reasons. Since I don’t know the reasons, I’ll give some common reasons. Using Automatic on a Roblox client’s graphic quality sets the quality to a good fit for the system. That can help stop the lag. Alongside that is excessive use of loops. Loops such as a While True Do can cause low FPS if overused.
Hope this helps. 
Even the lowest graphic setting used, players still gets low fps. Also i don’t think the problem is while true loops. I think the main reason is gun system. (NoCol)
High graphics quality level, particle effects, and I believe large amounts of raycasts would all be laggy
(not sure about the last one, but it seems like so)
Well, it may just be because of the systems. The players may have potato computers. I suggest testing it out on a better PC to see.
this is what i think:
scripts that cause memory leaks?
dunno man, i dont know anything about NoCol
try using less assets maybe??
either all that or it’s just their/your computer
maybe even code a ‘low-quality’ setting if possible
Moving parts can cause things to slow down if there are lots of them.