And the fix for the sudden but inexplicable plummet in video performance, especially pixel shaders?
Roll back the system to three days prior, before I installed the Visual C++ 2013 Redistributable.
Damn it all, #Microsoft, if installing such a major component of your own can do something so apparently unrelated as that to Windows 10, why does the OS let me install the damn thing at all?
*sighs* Still, technically better than Windows 7 and 8....