the board supports and runs DDR2 ram only ........... max is 4gigs each slot. (16gigs)
there is NO great difference to how fast a card will operate in pci-e 1/2 or 3............ big myth./selling point.
the ram on the video card has nothing to do with system ram. different entity......... you can run a card with DDR3 or DDR5. doesn't matter.
the 5450 will run fine provided the drivers are installed for it.