Good to know! I've tried it on my partner's system as well (slightly higher specs, GTX 1080 and AMD 8350, same OS, 16gb RAM) and the same situation occurs there too, let me know if you find anything, looking forward to experience this in its fullest! Thanks for your hard work on this!
I just posted this to Neko but will just paste it here as well in the hopes that it makes some sort of noticeable change.
I'm looking at the itch build as we speak and am unable to replicate the issue as of yet. I'll keep posting suggestions though in the hope that one of these things may correct whatever issue is occurring.
Do you have Vsync enabled inside your Graphics Card Dashboard/Settings? If so, could you try disabling it? I noticed that having it enabled drops the FPS noticeably for me.