There's times where I get some lag during prime time but it's not that bad in that regard.
The game does have several performance issues though. One is a vram issue where it fills your vram no matter what. During the betas I also had the performance degrade over time (not game progress), which required a restart of the game client to get back to full performance. I heard some people still experience this, so maybe this was just fixed through Linux drivers on my end instead. There's another issues however that is still ongoing: The game sometimes when you teleport or alt tab just degrades performance. You can usually fix this by toggling certain graphics option, like the shader quality back & forth or the smooth shadows off & on. I didn't notice a vram difference after that so I'm not sure if it's related to that or not but at least it is a quick momentarily fix until it happens again. Not sure if it works under Windows but I'd give it at least a try.
Edit: Skip the lag comment. It's been unplayable rubberbanding now.