I just bought ark yesterday, and yes, I know I'm a bit behind the times, and I opened it up, and it was running smooth. I don't have the beefiest PC, but it's an Alienware Aurora with an I7 core, so it runs almost every game alright, but I can't run doom for beans, if you catch my drift. Anyway, since I can run most games pretty well, I put the graphics on high. I started playing and it was unbearably laggy. I changed the settings for a few hours and it only runs "smooth" on the lowest settings. My PC specs are above the RECOMMENDED, so unless they decided to make the recommended specs the minimum, this shouldn't be happening. Are there some settings that need changed, or am I just over looking something obvious?
I had the exact same problem with ARK. All I had to do was go onto NVIDEA application on your PC and make sure my drivers were up to date and make sure that my game was optimised on the application.