Ive been playing since April and i have had average framerates on a not so good computer. When I started downloading addons and mods it didn’t seem to affect my FPS, but now i have had extreme lag during singleplayer and multiplayer. I think I’ve downloaded too much stuff.
you could try Power Krews G-Clean, on a light clean it can resolve manny chache erros generated my garrymod and speed up you load times a little. A Heavy clean will reset your garrysmod back to its original form without anny addons or modifications of anny sort.
You can get this software here: