Large facilities like dorms will usually have multiple routers/wifi repeaters which all have the same name to their wifi network. So it could be possible that your devices are connecting to different routers in both rooms, one might be close but has shitty bandwith (maybe due to technical issues or too many devices connected) and one is maybe further away but offers much higher network speed. Your devices will usually prefer the router which they get the best connection to, even if that routers network speed sucks.

Sadly I don’t know if there are ways to overwrite your devices preferences for which router they should connect to, but I could imagine that there would be software solutions to this (if it’s in fact a router issue).