Crossfire 101, master board question

[fishboi]

My sig has my rig's details. I have the MSI x1900xt v-card:
http://www.msi.com.tw/program/products/vga/vga/pro_vga_detail.php?UID=723

At the bottom it says - NOTE: Master board is needed for this slave board to start CrossFire.

What does this mean? Will two of these exact same cards run CrossFire, or do you need a "master card" to get it going? Who makes these master cards?

Thanks!

 

[fishboi]

Never mind, I need one of these:
http://www.msi.com.tw/program/products/vga/vga/pro_vga_detail.php?UID=736

Must have DMS output.

 

[TheGreatGrapeApe]

Yeah, it was good in theory, but ATi didn't make enough master cards, they were rarer, thus more expensive, and then they didn't keep stock to sell later.

People truely out of luck are the X1800 generation, since the X1800CF master is one of the rarest cards out there (I wonder if the sold less than the GF7800GTX-512?)