I have to chime in that the latest update has even affected me, who have NOT converted to UDL yet. I have a couple of maps. Sure they do use a fair bit of Legacy DL for iron bars and stuff, so I'm not saying those maps are not resource heavy. However.... before the UDL update, it worked like this: Player launches game and enters semi empty loading page. Memory usage increases a little bit, not strange at all. But then it stops, since nothing new is added/happening, etc. Player is moved to resource heavier map. Memory uses starts climbing. Also not weird at all. Eventually, memory usage reaches the point it needs, and stabilizes at it's new higher memory usage, since the map uses more memory. Again nothing weird at all. Player is moved to less heavy map, or back to semi empty loading page. Memory use starts sinking since it doesn't use as much memory on that page. So, that's nothing weird. But then the recent UDL update came... which I have not converted to. I'm still on Legacy. So how does the list above look like after that update? Should be similar no? Player launches game and enters semi empty loading page. Memory usage increases a little bit, not strange at all. But then it stops, since nothing new is added/happening, etc. Player is moved to resource heavier map. Memory uses starts climbing. Also not weird at all. Memory is still climbing. It doesn't stabilize, it just keeps going until I move away from the map. And this is even if I just move the player there, and then the player doesn't do a single thing. Still climbing. So I move the Player back to the semi empty loading page. Memory use ... is not climbing anymore. But.. it's also not sinking. It stays at peak it had at the previous map. And yes, the memory climb does not have a roof either. When I opened a small map that did have a bit of DL, sure, but it was small, and the memory was climbing. Eventually the memory would climb until I have no available memory left in the computer, where as Firefox completely grinds to a halt, and it takes about 20 minutes just to shut down because the entire system is halted, including the mouse being extremely laggy. And this is without UDL, on maps that worked without issues before the UDL update. Some kind of memory leak has most likely been introduced which just keeps eating more and more memory until you kill the process, because moving to a more lightweight map doesn't help, it will never ever sink again until you Exit Game .