We have two older Dell Optiplex 990 systems with AMD Radeon HD 6450 graphics adapters that have a DisplayPort and DVI-I dual adapters.  Both systems currently support two 1920x1200 monitors and we are interested in moving to three.  The AMD site says that the 6450 supports "up to 3" monitors, but apparently some versions of the 6450 have three connectors.  The DVI-I connector is of the dual type and is described as dual, but many of the DVI splitters I find are clearly for replicating the same content on both monitors, which is of no interest to us.  I have been told on another forum, not very authoritatively, that the third monitor would have to use a spliter on the DisplayPort connector.

Does anyone know for sure whether we can support three monitors with this card and, if so, which connector we need to use (or even a recommended connector)?