joe213 I didn't see the Godot part at first. I thought it was just the browser giving you problems. Unfortunately, I'd think Nouveau will probably give you the best performance. The proprietary blob probably doesn't properly support it anymore, and the Linux support Nvidia offered while it was supported was lackluster.
Hardware accelerated compositors can be hell on those old cards. Even xfce has one enabled by default (at least on Debian). Also, if you're running software under Windows 7 without a driver, are you sure they aren't being software rendered?
Sorry, just trying to cover the things I haven't seen in the thread yet.