The correct computer model I just purchased is 'HP Envy 750 247c'
if its the i7-6700, it would be shy of 2x faster than your old i5 desktop.
the i7-6700 and gtx 745 would be ok for HD timelines with just a few gpu effects and very lite lumetri use.
if you got the pc for a good price and wanted something better than the gtx 745, you could check if it will take a gtx 960 4gb.
if you want something more powerful for say 4k timelines, hp sells the ENVY Phoenix 860se with the i7-5820k and gtx 970.
As usual the low cost "leader" models that big manufactures like HP put out they have really skimped on the power supply in that unit, it is only 300 watt and therefore does not have any expansion capability internally to eventually upgrade your graphics card. That GPU draws 55 wats. Apparently there are no single width 900 series card let alone at 55 watts.