Re: double graphic card

SLI connectors can do different things depending on the engineering, and you need to read up on SLI compatibiltiy of the HP FX3800.  Start here:

http://la.nvidia.com/object/quadro_sli_compatible_systems.html

Then go here:

http://www.nvidia.com/object/sli_multi_os.html

It is more complex than meets the eye........