Dongles / Adapters / Converters
This is a list of supported dongles:
http://support.amd.com/us/eyefinity/Pages/eyefinity-dongles.aspx
active = some electronics converts the signal
passive = the card supplies the signal natively
EDIT: If your card has more than 2 (Mini-)DisplayPort outputs (i.e. 4,5,6). Then any 2 of them are classified as DP++, and the rest are classified as DP. DP++ signifies that the port is capable of producing a DVI signal, i.e. you can use a passive adapter with this port.
Any 2 ports can be used with passive adapters, the remainder must be used with active adapters.
VGA
All of the VGA dongles are listed as active (bit of a surprise, i thought that the one i’m using with my macbook is passive. When you cut one open, there’s some chips, but also 5 shielded lines leading to the PC, the same as a native VGA signal).
EDIT : After some time, there’s been no evidence to dispute that all VGA adapters are active. You can presume this to be true.
Max resolution is same as single link DVI (1920x1200), i.e. bandwidth for TH2G resolutions:
DVI single link
The DVI-D single links come in passive and active (1920x1200)
(same TH2G resolutions as VGA)
EDIT:
These are approximately £20
DVI dual link
The DVI-D dual links are all active (as expected)
Max resolution 2560x1600, which of course supports all TH2G resolutions
(This is necessary for the highest TH2G resolutions
EDIT:
So far, these all require external power (i.e. power from USB)
These are approximately £100
TH2G = Matrox TripleHead2Go