After numerous edits, I think I have conclusion that GL_LINES are very slow under win7. I can get substantal speed increase by simply changing GL_LINE elements to GL_QUAD elements and drawing very narrow boxes.
We draw thousands of GL_QUAD elements in the time it takes to draw half a dozen GL_LINE elements
If you’re using GL_LINE_WIDTH or GL_LINE_SMOOTH then these aren’t guaranteed to be hardware accelerated, and it sounds like that’s exactly what you’re running into.
I don’t see reference to either of this attributes in our code. GL_QUAD solves the speed issue, but Quads disappear when viewed from the edge, while lines are visible from any angle