Hmm, Workstation class card huh, Well makes sense, Workstation GFX card in a Workstation Mac.That would make sense to me given that this was considered a Workstation-class GFX card(at least before flashing).
EDIT:
If I'm reading the data sheet correctly, that's right
http://static.highspeedbackbone.net/pdf/ATI_FireGL_X3-256_DataSheet.pdf
EDIT: Top-of-the-line card huh? I wonder how well this thing would be with Sims 3 on Windows.....