Hi ophir goldberg,
1. You can connect 3 displays 2x DVI + 1x HDMI without using active adapters.
2. You can connect 4 displays by using 2x DVI + 1x HDMI + 1x DisplayPort (DisplayPort display required)*
*If you do not have a DisplayPort Display you must use an active adapter
3. You can connect to a maximum of 6 displays by using a MST Hub via the DisplayPort output
Note: MST Hubs are DP++, if you require a conversion from DisplayPort to HDMI for example, you can use a passive adapter
Using an active adapter instead of a passive adapter utilises a small chip inside the adapter that converts the DisplayPort signal to a signal that is usable by a DVI/HDMI connection, while still maintaining the DisplayPort standard. Using a passive adapter just converts the DisplayPort output to a legacy/passive output. Active adapters are only available using the DisplayPort output, as there are currently no supported active adapters that use the DVI, VGA or HDMI outputs.
For a list of certified adapters, you can refer to www.amd.com/dongles, as these are adapters that our certification team has tested with our cards and found them to be compatible with all AMD products. For reference regarding the difference between single-link and dual-link DVI adapters, the single-link has a maximum resolution of 1920x1200, while dual-link adapters (featuring more pins) can support up to 2560x1600. This relies on using a dual-link DVI wire as well, however.
If you are unsure how to determine if your DisplayPort adapter/cable is active or passive, any cable with Mini DisplayPort or DisplayPort on one end, and VGA/DVI/HDMI on the other end will be passive. If the adapter features an additional USB connection, or has the word "ACTIVE" physically imprinted on the adapter, then it will be active, otherwise it is most likely a passive adapter.