MacPro: Issues with Internal Airport Card

Several readers have reported performance issues with the airport card installed in their Mac Pro.
We have performed some test, and results are clear: even located 1 meter away from a Airport Express station, the wifi signal captured by the Airport card in a Mac Pro is not getting to 100%...
Concerning data transfer speed, the Mac Pro hardly get more than 550KB/s while a MacBook Pro in the same conditions gets 3.3MB/s.
And the worst scenario, creating an Airport network from a Mac Pro, in this case a MacBook Pro can not get data transfer speed over than 150KB/s.
We have of course opened the Mac Pro and ensured that all antenna were plugged correctly. When booting the machine with WinXP, then the wifi signal is perfect as we would have expected it with OSX too. So this test confirms that the current issue with Airport card in Mac Pro is directly linked to dedicated driver in OSX.
If you remember, Apple had postponed the shipment of Airport-enable MacPro models (as BTO) for several weeks; one can bet that it was probably to try fixing the issue before delivering the computers.
We would be interested to get your feedback about this issue if you own a Mac Pro or a recent iMac Core 2 Duo: please react to our new hardmac forum: hardmac forum NEWS