Gmod problems that annoy me

So every time i join a server for the first time i cannot play. I either need to wait like 1 hour or reconnect. I made sure its not just me cause my friend had same issue. It does happen with multiple servers not just one. Also lately i noticed that i am getting quite bad stuttering with Gmod. I have pretty good PC with up to date drivers so it shouldn’t be a problem. But even when i have 120-300 fps things feel laggy and stuttery. I have tried reinstalling Gmod about twenty times still nothing. So what would be the easiest way to fix all of those problems ?

PS: Windows 8.1