Playtesting is laggy in only one game

I recently installed a new graphics card in my computer, its drivers are updated and runs everything fine. Regular Play Testing runs fine, but for some reason when i try local server testing with any amount of players it gets extremely laggy. I changed nothing in my game since replacing my graphics card so im not sure whats causing this extreme lag. And it only happens in this game, ive tried playtesting other, larger projects and those run fine.


Processor: Ryzen 9 5900X
GPU: RTX 4070
Storage: 2TB M.2 SSD & 1TB SATA III SSD