Be honest why don't you? The XP on Mactel hack is not using the full power of the video display. The hack yields joe-basic video without acceleration, without directx . . . hell, it doesn't even fill the full monitor screen yet.
It is a lobotomized video throughput, nothing more.
What you claim is not the case, the video works in the most primitive fashion possible (like using the "Super VGA" on a windows install).
And for the love of God, it's OSX, not "OSx."
Read this thread, it's state a few times about the drivers being almost the same.