Was there any single beep during POST that indicates that the video card passed its POST?
Did it beep for the FX1300 and not for the HD5450?
If there was no beep with the HD5450 then that video card did not pass its POST.
No beeps, no beep, no letters or words on the screen, absolutely nothing except rotating fans and the HDD led on for the HD5450.
For the FX1300, all normal beeps, POST, screen flashes etc and a completely stable correct screen capable of videos, CAD etc.