Barely any symbols (2-3 maybe?). I used to have up to 100 artboards, with tons of images and it worked flawlessly. It now starts to slow down after only 30 or something. It doesn't matter if it's all vector for example. I even cleaned up my fonts to have a really limited set available and enable ones I need, when I need them. It's a mac mini (late 2014, 16gb of ram, 512gb ssd to a Dell 3415").