Performance is the game's biggest issue right now. I really wish they'd focus on that above all else. Best piece of advice I can give is that if you have a 2GB card don't try to go above medium textures (which unfortunately look like ass). The game really wants 3-4GB of VRAM for some inexplicable reason.
Much of the performance problems are the fault of the game's design too. Eggs are used to make kibble, which is the only way to tame high end animals. Not only does it take vastly less time, it also vastly increases the final level of the pet. A L120 herbivore tamed with kibble becomes L178 and takes at most 2-3 hours; tamed with mejoberries you'd lucky to get more than L130 and can take up to 14 hours. This is all cool in theory, but the actual result is that people want eggs now. Lots and lots of eggs. At one point my tribe had 42 scorpions, and to say that caused people's computers to go into slideshow mode would be the understatement of the year. We got rid of the scorpions once we hit 1000+ eggs, since that's almost 20 max level T-Rex tames, but we still have 8 stegos (-> birds), 10 turtles (-> brontos), 16 or so dilos (-> ankylos and doedis), and at least a dozen birds (-> spinos). That's just the stuff we keep around for eggs too, except for the birds which we'd have anyway. On top of that we have a shitload of rexes, spinos, pteranodons, ankylos, sabertooths, raptors, a bronto, a couple mammoths, etc.
Now consider that this was up until very recently a tribe with three main members who did all the work. There are tribes out there much, much larger than us, and they have even more stuff tamed and built than we do. Then there's all the people who built stuff and then quit, which is very difficult/costly to remove on a PVP server, but still contributes to server and client lag all the time.
Bottom line, the performance was never great, but it was manageable for a while. The race to tame everything under the sun for egg production has made practically every base into a slideshow when you first load it (which can be deadly due to turrets) and the server lag just keeps getting worse and worse since anything built with stone or metal is usually permanent.
Still a really fun game though, if you choose your server wisely. I can't imagine playing on one of the shitholes that is overrun with Chinese streamers or locked down by a bunch of kiddies who try to extort everyone else.