First of all, i am very sorry for that cheap iWeb how to, but i am too lazy to code it in HTML and don’t have the time.

i Used two ATI Radeon HD 4870 GPU from HIS

I had to flash them, i don’t know where i get the flasher, i’ll post that later.

Update: The Flasher is available Here, just put all three files on Macintosh HD (/) and launch 4870Flash.app

The Mac Pro has a 1kw power supply but on the logic board there are only two power connectors for Graphics cards, this is a Problem because we need 4x 6 pin power.

So i cuted the cables of the 2x 4pin molex to 6 pin graphic power adapter and conected them like tis: (for a bigger image click on this link) here is also a link where you see how i conected the cables: link

you will notice, that the adapter which was shipped with the graphics card has only 5 pins connected, so just let this cable like it is, it worked fine for me

now insert first the first card, flash it and then the second card. remember, let the original card inserted while flashing, because the 4870 cards will only work after flashing, so u need a other card where you have conected the monitor.

The Flasher is available Here, just put all three files on Macintosh HD (/) and launch 4870Flash.app

After that, remove the original Graphics card and insert the 4870 card like this:

it is verry important to conect the power cables like this: else you will have only a black screen!

After that enjoy your mac pro.

if you have a question, feel free to contact me

greetings

madmike88252