[badsectoracula]

IMO that sounds either like a bug in Nvidia's drivers (IIRC OpenGL doesn't require that sort of alignment) or -more likely- your code having some other memory related-bug (e.g. accessing data out of bounds) that the extra bytes you got from alignment masked it.

[magicalhippo]

Nah it was definitely NVIDIA's fault. As you say there's nothing in the specs about alignment of those buffers, so they shouldn't be using aligned load instructions.

However Microsoft's malloc at the time was indeed returning 16-byte aligned buffers so they probably didn't notice it in internal testing.