(In reply to Paul from comment #9)
> it's less obvious, but there still appears to be screen tearing

How does that manifest, and when you do what?

> when running via openGL 3.1 using full-screen-repaints.

FWIW, since DRI3 is enabled, "Re-use screen content" is the most efficient
setting.

> It's also reasonably obvious that for some GUIs their buttons will update
> their two triangles across two frames instead of one, this seems to be a
> much rarer occurrence with the above settings however.

Yeah, this is unavoidable with apps which use X11 drawing primitives targeting
their windows directly.