Originally Posted by whe3ls
for soft fire u need a crossfire ready card and a regaler card internal birge u need to of the same card or same style 16500 xt 1950 pro 2900xt dongle in need a crossfire master card and a salve card be it a 1800xl or xt master or a 19s0 master card and a pro xt or xtx
After finally understanding it... I disagree.
'Softfire' is accomplished by using identical cards WITHOUT the internal bridge or the external cable. No 'hard wire' is used, and all communication goes through the motherboard, hence the name 'softfire'. This is only possible with lower-end cards like the X13xx, the X16xx (except X1650XT) series, the X1800GTO, and the X1900GT.
There are two versions of 'true' Crossfire: one using an internal bridge, like SLI, and one using an external cable and a master/slave card configuration. The version with the internal bridge gets rid of the need for a master card, and two 'regular' cards can be used. This only works with the X1650XT and the X1950PRO cards. The most common version of Crossfire is still the master Crossfire Edition card in combination with a regular card as slave. Unfortunately, Crossfire edition cards are sometimes hard to find and expensive.
Here is the chart of possible Crossfire set ups. The color indicates what sort of connector, if any, is used.