@ pm-r: always, with non-Apple GPU cards on a Mac Pro, the boot logo gets omitted.
This IMHO was normal when you used a PC GPU on a Mac Pro
The reason for this is a firmware difference between Apple & non-Apple GPUs.
Boils down to Little Endian vs. Big Endian code in the firmware.
With older Mac Pros this issue was unsurmountable unless the user reflashed the firmware of the GPU card.
Since 3.1 Mac Pros (or maybe a more recent version of Mac OS, don't remember which), the issue has more or less been fixed.
@ MacFury: did you use the DosDude 1 patcher?
BTW: could you post a pic of your magnificent setup?
Dankjewel hoor! (excuse my French)