The following 2 lines should be 2 lines of greek letters and they should be perfectly identical, should be rendered identically.
The 3rd line should be the same greek letters but the letter spacing and letter height should be different and should be using a different font.

α Α β Β γ Γ δ Δ ε Ε ζ Ζ η Η θ Θ ι Ι κ Κ λ Λ μ Μ ν Ν ξ Ξ ο Ο

α Α β Β γ Γ δ Δ ε Ε ζ Ζ η Η θ Θ ι Ι κ Κ λ Λ μ Μ ν Ν ξ Ξ ο Ο

α Α β Β γ Γ δ Δ ε Ε ζ Ζ η Η θ Θ ι Ι κ Κ λ Λ μ Μ ν Ν ξ Ξ ο Ο

Firefox 3.0.4, Opera 9.62, Safari 3.2, Safari 4.0, Konqueror 4.1.1, NS 7.2, Hv3 TKHTML alpha 16, Amaya 10.0.1, Seamonkey 2.0a2pre all pass both of these tests.

Update: This bug has been FIXED in Internet Explorer 8 RC1 (build 6001.18372) released on January 26th 2009. Otherwise, Internet Explorer 8 RC1 PASSES this specific and particular testcase.