My computer's performance plummets when there's no internet. Why the fuck do you need the internet to work?! Just how much data are you sending to the NSA?!

That sounds like some wonky application thing rather than an OS.

@N00bPancakes I have seen Windows computers (XP I think), do weird things because of network drivers. Like run dog slow.

I would recommend finding the vendor supplied network driver for your network devices. Do NOT rely on Microshit to update your device drivers. Microshit often installs broken drivers.