Seems that HP thought about having 2 PCI-E slots....maybe for SLI?
i dont think so since it would be single slot and X16/X4 electrically, at last not SLI since it wouldnt get the SLI ready from nV (need a X8 minimal iirc) but CFX has no minimum, like my FM2A88M Ex4+ who has Crossfire ready and can only do x16/x4 2.0/2.0 or X16/X4 3.0/2.0 (with a Kaveri Apu).
EDIT... wait ... the Powercolor 5450 is single slot ... and cheap enough for me to try something with that DC7900 ahahahah ... (either way i need a 2nd 5450 i will never run a GMA 3100/4500 again)
wish i had someplace like that
yeah ... on 3 PC's they sent to the dump only 1 was not re usable (DC7600 PIV S775) the 2 other :
DC7700p
tech diagnostic : motherboard fried,
my experience : onboard video out of order (work fine until you install the video driver)
cost of the reparation: less than 27chf for a 5450
bonus: free Win XP Pro license (even with the end of support i still love XP )
DC7900
tech diagnostic: motherboard fried (Uh? does he know his job?) and PSU too (oh i bet he added PSU to make believe he was knowing what he did )
my experience: oh well started just fine on the VGA or the DP after removing some dust and other joyful things... seems that one SATA port recognize the HDD in the bios but not in win7 (working on it)
cost of the reparation : 0chf ... aherm ...
bonus: free Win Vista Business license (whaaattt maybe its vista but still it is free .... on a second thought i think i will keep it under 7 Pro ... )