I've solved my performance issues under Windows. It turns out that Soeedstep was fucked up. Disabling it has *massively* improved performance. Like, fucking, night and day. Suddenly it's running so fucking smoothly, Clone Hero gets around 400 fps with 8x MSAA, and I'm willing to bet I could actually get Sonic Forces to run reasonably well now. It's beautiful.
2020 is the year we unabashedly like the things we like regardless of what other people think of them