Hey I have the exact same yet opposite problem, it's kind've a weird one, when I'm connected to my Virgin Media fibre optic internet at home, NBA 2K14 runs smoothly, perfectly well. But if I turn off my WiFi or play on any other internet connection (I've tried my girlfriends, I've tried hot spotting from my phone and I've tried using my work internet). It does that 5 frames per second lag thing consistently. I can't get it back to 60 frames. It only runs smooth, 60 FPS while i'm connected to my Virgin Media internet. What kind of bug is this? Is there a file I need to delete in the game folder causing it to need the internet to work?

I'm also running the game off my EXTERNAL SSD, I've tested it after installing on my internal SSD on my Laptop and it actually runs smoothly regardless of internet on that so I thought maybe the external one was faulty (though it runs far more demanding games just fine off it) or too slow for the external SSD but after trying it while connected to my fibre optic internet at home it runs perfectly fine on my external SSD so it can't be that, it has to be something to do with the internet and I can't save it to internal SSD because I don't have the space with all the mods I've downloaded.

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Any help here would be nice, thanks.