On my case, it is not really laggy, but if I want to do anything else, such as browsing internet, and having another game opened, it really lags everything on my PC.
First off, I have came to a conclusion that the freaking client eats a lot of RAM, and I have only 8GB, and while doing these other things simultaneously, it eats up all my RAM. Of course I am not supposed to run everything at once, but Naruto Online is nothing of sort of a game that requires so much RAM, which lately has increased a thought in my head about whether or not this client silently is mining our PC's for cryptocurrency. I wouldn't be surprised, it's Tencent.

Other thing is, I have an old Caviar Green HDD, it really gets to 100% load when I have opened client, two accounts, and doing either a net browsing, or playing another game. So I have two reason. What I have noticed regarding RAM, is that an average game, such as Fallout 4, or Kingdom Come Deliverance, only uses 1,3 - 1,8GB of RAM, and from my 8GB it's so little that I can easily afford to run another game and be fine, or have a internet opened, which I often do, and I have no problems. But with Naruto Online opened, *...it totals up to 6,7 - 7,4GB of RAM, makes my HDD run at 100%, and so on. CPU on the other hand is fine and no problems, I got i7 2600k @stock clock settings (can't overclock because I don't have the mobo for it, and cooler appropriate).

I think I will start Naruto through the facebook/browser rather than client, and see how much it eats total that way. If less, then the client is outdated, as I have always mentioned it when I get the chance, or Tencent is mining our PC's for cryptocurrency. Since the client hasn't been updated since the western server releases by OG, except once soon after, which is weird. Such things should be updated and improved as a quality standard, but they are not even bothering to pretend that they are doing it, and this totally isn't a "if it works, don't fix it" kind of thing...