So far as I can tell, I get similar frame-rates under X11 with Wine as Windows users do on the same hardware. Intel's video drivers are wonderful, including for 3D acceleration, it's just their hardware that's lacking.

I must have hallucinated playing 3d games on my intel-based systems. (Of course, performance isn't great, but it doesn't work bad at all, at least in my experience).

Intel has really stepped up in the past few years. But it's not too long ago when their h/w was pretty much unusable in Linux so their track record isn't very good.